Prior Vaccination History Research Articles

Onward transmission of measles virus among vaccinated cases in a large community outbreak in Auckland, New Zealand, 2019

Background: Isolation of cases and quarantining of non-immune contacts are the mainstay of measles outbreak management in elimination settings. Serology testing of exposed contacts may not be feasible in large outbreaks; therefore, vaccination history is used as a proxy for determining immunity to measles and thus prevention of onward virus transmission. This study sought to investigate the risk of measles virus transmission from individuals with a history of one or two doses of measles-containing vaccine (MCV). Methods: Retrospective analysis of data from measles cases reported to Auckland Regional Public Health Service during the 2019 Auckland region measles outbreak. Vaccination history was verified using patient records and the New Zealand National Immunisation Register. Onward transmission was determined through case interviews and assessment of exposed contacts. Results: 1451 measles cases were assessed as eligible for vaccination at the time of measles outbreak. Of these, 1015 (70.0%) were unvaccinated, 220 (15.2%) had unknown vaccination status, 139 (9.6%) had received only one dose of MCV and 77 (5.3%) had received two doses of the vaccine. Compared to unvaccinated cases, the odds of onward transmission were lower among those with one dose only (OR 0.41, 95% CI: 0.20–0.75) or two doses of MCV (OR 0.44, 95% CI: 0.17–0.95). Median time since vaccination was longer among those with onward transmission compared to those without onward transmission for one and two doses of the vaccine, suggesting a potential effect of waning immunity among this cohort. Conclusion: These findings support the hypothesis that measles cases with a history of prior vaccination are less likely to transmit the virus to others compared to unvaccinated cases. Such information can be used to support decisions around quarantine requirements for vaccinated contacts in future measles outbreaks.

Differential COVID-19 case ascertainment by age and vaccination status in Victoria, Australia: a serosurveillance and record linkage study.

To compare serological evidence of prior severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection with linked coronavirus disease 2019 (COVID-19) case notification data in Victoria, Australia, and to determine in vitro SARS-CoV-2 neutralisation activity based on prior infection and vaccination history. Four cross-sectional serological surveys were conducted between 30 June and 31 October 2022 (a period of Omicron BA.4/BA.5 dominance) using 1,974 residual serum samples obtained from the Victorian Infectious Diseases Reference Laboratory. Serological results were linked to COVID-19 case notification and vaccination data. Surrogate virus neutralisation testing was performed to obtain in vitro inhibition estimates by anti-nucleocapsid serostatus and COVID-19 vaccination history. Adjusted anti-SARS-CoV-2 spike and nucleocapsid seropositivity by sex, age and region of residence; adjusted proportion of cases notified by anti-nucleocapsid serostatus, age and number of COVID-19 vaccination doses received; adjusted percentage in vitro inhibition against wildtype and Omicron BA.4/BA.5 SARS-CoV-2 variants by anti-nucleocapsid serostatus and COVID-19 vaccination history. The prevalence of anti-SARS-CoV-2 nucleocapsid antibodies was inversely proportional to age. In October 2022, prevalence was 84% (95% confidence interval [95% CI]: 75-93%) among 18-29-year-olds, compared to 39% (95% CI: 27-52%) among ≥ 80-year-olds. In most age groups, approximately 40% of COVID-19 cases appear to have been notified via existing surveillance mechanisms. Case notification was highest among individuals older than 80 years and people who had received COVID-19 vaccine booster doses. In vitro neutralisation of Omicron BA.4/BA.5 sub-variants was highest for individuals with evidence of both prior infection and booster vaccination. Under-notification of SARS-CoV-2 infections in the Victorian population is not uniform across age and vaccination strata. Seroprevalence data that give insights into case notification behaviour provide additional context for the interpretation of existing COVID-19 surveillance information.

Long-term risk of autoimmune diseases after mRNA-based SARS-CoV2 vaccination in a Korean, nationwide, population-based cohort study

The long-term association between mRNA-based coronavirus disease 2019 (COVID-19) vaccination and the development of autoimmune connective tissue diseases (AI-CTDs) remains unclear. In this nationwide, population-based cohort study involving 9,258,803 individuals, we aim to determine whether the incidence of AI-CTDs is associated with mRNA vaccination. The study spans over 1 year of observation and further analyses the risk of AI-CTDs by stratifying demographics and vaccination profiles and treating booster vaccination as time-varying covariate. We report that the risk of developing most AI-CTDs did not increase following mRNA vaccination, except for systemic lupus erythematosus with a 1.16-fold risk in vaccinated individuals relative to controls. Comparable results were reported in the stratified analyses for age, sex, mRNA vaccine type, and prior history of non-mRNA vaccination. However, a booster vaccination was associated with an increased risk of some AI-CTDs including alopecia areata, psoriasis, and rheumatoid arthritis. Overall, we conclude that mRNA-based vaccinations are not associated with an increased risk of most AI-CTDs, although further research is needed regarding its potential association with certain conditions.

Leptospirosis as a cause of infertility in Uruguayan beef cattle

Leptospirosis, caused by pathogenic spirochetes of the genus Leptospira spp., is a globally significant zoonotic disease that affects humans and animals. In cattle, leptospirosis is associated not only with overt clinical manifestations but also with reproductive diseases, including infertility. This study assesses the potential correlation between leptospirosis and infertility in Uruguayan beef cattle. A case-control study involved 31 beef herds with no prior history of Leptospira vaccination. In each herd, veterinarians identified 10 non-pregnant (cases) and 25 pregnant cows (controls) using ultrasound, and blood and urine samples were collected from each cow. Serological diagnosis was performed using the Microscopic Agglutination Test (MAT), and quantitative PCR (qPCR) was used to assess Leptospira excretion. Additionally, antibodies against bovine viral diarrhea virus (BVDV) and infectious bovine rhinotracheitis (IBR) were tested. The results demonstrated an association between seropositivity to the Sejroe serogroup (cut-off 1:200) and infertility in cattle (OR=1.31; p-value=0.06). Furthermore, the level of Leptospira excretion (qPCR) in urine was associated with increased infertility risk, with cows excreting over 100 copies per mL of urine having the highest odds of infertility (OR=2.34; p-value<0.01). This study suggests a potential association between leptospirosis and infertility in Uruguayan beef cattle, emphasizing the importance of both serological and molecular diagnostics for assessing reproductive health in cattle herds. Future research should explore the impact of Leptospira serogroups on other reproductive disorders in cattle.

Cross-Reactive Antibody Responses to Coronaviruses Elicited by SARS-CoV-2 Infection or Vaccination.

The newly emerged SARS-CoV-2 possesses shared antigenic epitopes with other human coronaviruses. We investigated if COVID-19 vaccination or SARS-CoV-2 infection may boost cross-reactive antibodies to other human coronaviruses. Prevaccination and postvaccination sera from SARS-CoV-2 naïve healthy subjects who received three doses of the mRNA vaccine (BioNTech, BNT) or the inactivated vaccine (CoronaVac, CV) were used to monitor the level of cross-reactive antibodies raised against other human coronaviruses by enzyme-linked immunosorbent assay. In comparison, convalescent sera from COVID-19 patients with or without prior vaccination history were also tested. Pseudoparticle neutralization assay was performed to detect neutralization antibody against MERS-CoV. Among SARS-CoV-2 infection-naïve subjects, BNT or CV significantly increased the anti-S2 antibodies against Betacoronaviruses (OC43 and MERS-CoV) but not Alphacoronaviruses (229E). The prevaccination antibody response to the common cold human coronaviruses did not negatively impact the postvaccination antibody response to SARS-CoV-2. Cross-reactive antibodies that binds to the S2 protein of MERS-CoV were similarly detected from the convalescent sera of COVID-19 patients with or without vaccination history. However, these anti-S2 antibodies do not possess neutralizing activity in MERS-CoV pseudoparticle neutralization tests. Our results suggest that SARS-CoV-2 infection or vaccination may potentially modulate population immune landscape against previously exposed or novel human coronaviruses. The findings have implications for future sero-epidemiological studies on MERS-CoV.

Covid-19 vaccine compliance among residents of Kathmandu Valley

Background: The Coronavirus disease 2019 (COVID-19) pandemic is a public health threat. Equitable access to safe and effective vaccines is critical to end the COVID-19 pandemic. Promoting the uptake of vaccines (particularly those against COVID-19) require the understanding whether people are willing to be vaccinated, and the reasons behind their decision. Objectives: This study aimed to assess COVID-19 vaccine compliance and factors associated with it among residents of Kathmandu valley. Methods: A cross-sectional analytical study was conducted among residents of Kathmandu valley through a pre-tested web-based self-administered questionnaire. A total of 390 respondents were selected to carry out this study. The collected data were entered into MS-excel and analyzed using SPSS IBM v. 25. Multivariable analysis was performed. Results: Vaccine compliance was found in 94.1% of 390 respondents. Among the respondents, 91.5% had low risk perception of COVID-19; 85.4% had complete prior vaccination history; 61.3% perceived COVID-19 vaccine as effective; 65.6% perceived. COVID-19 vaccine as necessary whereas only 24.6 % believed the COVID-19 vaccine to be safe. Regarding COVID-19 vaccine compliance, females demonstrated a 3-fold higher likelihood than males (AOR= 3.0, 95%CI: 1.01-9.21). Complete vaccination history which had 31.9 times higher odds than no vaccination history (AOR=31.96, 95%CI: 9.72-105.14), perceived vaccine effectiveness which had 7.7 times higher odds than perceived ineffective (AOR= 7.75, 95%CI: 2.37-25.38), and high social influence which had 7.7 times higher odds compared to low social influence (AOR= 7.72, 95%CI: 2.19-27.12) were the associated factors with increased compliance. Conclusion: This study revealed significantly high vaccine compliance rate in Kathmandu valley. Sex, complete vaccination history, perceived vaccine effectiveness and high social influence were the determinants for vaccine compliance which indicated the importance of ensuring people trust the vaccine's safety, utilizing social influence to encourage vaccination, and tailoring strategies to suit different demographics.

Immunogenicity of Intradermal Versus Intramuscular BNT162b2 COVID-19 Booster Vaccine in Patients with Immune-Mediated Dermatologic Diseases: A Non-Inferiority Randomized Controlled Trial.

The intradermal route has emerged as a dose-sparing alternative during the coronavirus disease 2019 (COVID-19) pandemic. Despite its efficacy in healthy populations, its immunogenicity has not been tested in immune-mediated dermatologic disease (IMDD) patients. This assessor-blinded, randomized-controlled, non-inferiority trial recruited patients with two representative IMDDs (i.e., psoriasis and autoimmune bullous diseases) to vaccinate with fractionated-dose intradermal (fID) or standard intramuscular (sIM) BNT162b2 vaccines as a fourth booster dose under block randomization stratified by age, sex, and their skin diseases. Post-vaccination SARS-CoV-2-specific IgG and interferon-γ responses measured 4 and 12 weeks post-intervention were serological surrogates used for demonstrating treatment effects. Mean differences in log-normalized outcome estimates were calculated with multivariable linear regression adjusting for their baseline values, systemic immunosuppressants used, and prior COVID-19 vaccination history. The non-inferiority margin was set for fID to retain >80% immunogenicity of sIM. With 109 participants included, 53 received fID (all entered an intention-to-treat analysis). The fID demonstrated non-inferiority to sIM in humoral (mean outcome estimates of sIM: 3.3, ΔfID-sIM [mean, 95%CI]: -0.1, -0.3 to 0.0) and cellular (mean outcome estimates of sIM: 3.2, ΔfID-sIM [mean, 95%CI]: 0.1, -0.2 to 0.3) immunogenicity outcomes. Two psoriasis patients from the fID arm (3.8%) developed injection-site Koebner's phenomenon. Fewer fID recipients experienced post-vaccination fever (fID vs. sIM: 1.9% vs. 12.5%, p = 0.027). The overall incidence of disease flare-ups was low without a statistically significant difference between groups. The intradermal BNT162b2 vaccine is a viable booster option for IMDD patients troubled by post-vaccination fever; its role in mitigating the risk of flare-ups remains unclear.

Vaccination in Kidney Transplant Candidates.

Kidney transplant (KT) candidates have historically low immunization rates against recommended vaccines. A retrospective single-center study of contemporary KT candidates was conducted to assess vaccination rates and vaccine uptake. All KT candidates ≥18 y evaluated between January 1, 2020, and December 31, 2020, were retrospectively reviewed for history of prior vaccination against tetanus, diphtheria, and pertussis; 13-valent pneumococcal conjugate vaccine; 23-valent pneumococcal polysaccharide vaccine; and recombinant zoster vaccine. Positive hepatitis A IgG total, hepatitis B surface antibody, measles, mumps, rubella, and varicella IgG were assessed as surrogate markers of immunity. Vaccine uptake among vaccine-eligible candidates was also assessed. Among 150 KT candidates, the rate of prior vaccination against tetanus, diphtheria, and pertussis; 13-valent pneumococcal conjugate vaccine; 23-valent pneumococcal polysaccharide vaccine; and recombinant zoster vaccine (latter among patients ≥50 y) was found to be as low as 11%. Hepatitis A IgG total, hepatitis B surface antibody, measles, mumps, rubella, and varicella IgG seropositivity rates were 30%, 66%, 88%, 78%, 90%, and 96%, respectively. Only 7 (5%) of 150 patients had complete immunization or seropositivity. Five (3%) of 143 vaccine-eligible patients declined vaccination. Hepatitis A vaccine declination was relatively common with 15 (16%) of 94 vaccine-eligible patients declining it. KT candidates have low baseline rates of prior immunization/seropositivity against most recommended vaccines. Overall vaccine uptake among eligible candidates was high.

Guillain-Barre syndrome before and during the COVID-19 pandemic in a referral center of Mexico.

During the COVID-19 pandemic, an increase in the number of Guillain-Barre syndrome (GBS) cases has been reported. To describe the clinical characteristics and prognosis of patients with GBS before and during the COVID-19 pandemic. Prospective cohort of GBS patients divided in two subgroups: before (2018-2019) and during (2020-2021) the COVID-19 pandemic. Clinical and paraclinical characteristics, as well as deaths, were recorded. A good prognosis was defined as independent ambulation recovery at three months. Two-hundred and one patients were included (123 during and 78 before the pandemic), out of whom 69% were males; age was 45 ± 16 years, and there was 2.5% of in-hospital deaths. During the pandemic, a higher frequency of the demyelinating variant (50%), bulbar cranial nerves involvement (44% vs. 28%), prior history of vaccination (16% vs. 0%), and a lower MRC score (30 ± 16.7 vs. 34.3 ± 17.7) were documented. An increase in the number of cases was observed from July to September (38 vs. 13). There were no significant differences in independent ambulation recovery or in the number of deaths. During the COVID-19 pandemic, a higher number of GBS cases were treated, out of which 16% were associated with the SARS-CoV-2 vaccine; patients treated during the pandemic did not have a worse prognosis.

Changes in Confidence, Feelings, and Perceived Necessity Concerning COVID-19 Booster.

The COVID-19 booster first became available to all adults in the U.S. in November 2021 and a bivalent version in September 2022, but a large population remains booster-hesitant; only 17% of Americans have obtained the updated vaccine as of June 2023. We conducted two cross-sectional surveys in 2021 and 2022 (n = 1889 and 1319) to determine whether changes in booster-related feelings or perceptions had occurred and whether they altered vaccination rates over time. We found that both positive and negative emotions had grown stronger between the two years, with the prevalence of annoyance increasing the most (21.5% to 39.7%). The impact of trust on booster intention more than doubled (OR = 7.46 to 16.04). Although perceived risk of infection decreased, more participants in 2022 indicated uncertainty or unwillingness to obtain a new booster than in 2021, while the proportion refusing a booster remained constant at 22.5%. Confidence in the COVID-19 vaccine and feelings of hope from the booster motivated acceptance; both were stronger predictors of booster receptivity than prior vaccination history. Our findings signal a need to rebuild trust by informing people of their continued risk and appealing to positive, especially optimistic emotions to encourage booster uptake. Future research should explore longitudinal trends in behavior and feelings toward new booster doses and the impact of prolonged vaccine hesitancy on infection rates.

#3767 THE IMPACT OF COVID-19 PANDEMICS ON THE OUTCOME OF 24 CHINESE PATIENTS DIAGNOSED OF MEMBRANOUS NEPHROPATHY RECEIVING RITUXIMAB THERAPY

Abstract Background and Aims Rituximab has been considered as the first-line immunosuppressive therapy in membranous nephropathy. Anti-CD20 depleting therapy is associated with prolonged B-cell depletion and has been reported to increase risk of severe COVID-19 infection in several rheumatic and neurologic diseases. However, few studies reported the impact of COVID-19 infection on membranous nephropathy in the status of B-cell depletion. Our study aimed to describe the impact of prior rituximab therapy on clinical outcomes of a group of Chinese membranous nephropathy within 6-month follow-up during COVID-19 pandemics. Method We prospectively conducted a cohort study of adult patients diagnosed of membranous nephropathy receiving rituximab therapy from Aug 1st to Nov 30th in 2022, in one tertiary hospital, in Beijing. Patients’ baseline characteristics (including demographic data, serum albumin, serum creatinine, 24-hour proteinuria, serum IgG level, peripheral lymphocyte subsets, medications, past medical history, prior COVID-19 vaccination history), clinical outcomes were recorded. We followed up all the patient regularly until Jan 31st, 2023. Results We included 24 patients with median age of 55 (27, 83) years old. 13 (54.2%) patients were on chronic immunosuppression with corticosteroids, calcineurin inhibitors, and/or mycophenolate mofetil. We followed up the patients within median 4.6 months since last rituximab infusion at the dose of 1 gram. During follow-up, 18 (75%) patients got COVID-19 infection including 16 non-severe cases and two severe cases requiring hospitalization and receiving intravenous dexamethasone. The overall COVID-19 vaccination rate was 33%. In subgroup analysis, the baseline characteristics were comparable between COVID-19 infection group and non-infection group. Vaccination rate in COVID-19 infection group was lower than that in non-infection group insignificantly (28% vs 50%, P=0.362), and the two cases of severe infection were unvaccinated with severe hypoimmunoglobulinemia. Circulating natural killer cell counts were significantly different between the two groups (365(63, 745) vs 194(23, 928)/μl, P=0.019), while neither CD4+T cells nor CD8+T cells counts showed statistically difference between the counterparts (CD4+T cells: 632 (227, 1231) vs 407 (230, 571)/μl, P=0.05; CD8+T cells: 496 (134, 1815) vs 306 (127, 728)/μl, P=0.179). No relapse of membranous nephropathy was observed after infection during follow-up. Conclusion COVID-19 infection was common in Chinese membranous nephropathy receiving recent administration of rituximab during COVID-19 pandemics. Low vaccination rate and prolonged B-cell depletion after rituximab infusion in this population may attenuate the protective effect of COVID-19 vaccine. Nature killer cells may play a key role in antiviral immunity. Patients should continue to maintain a high adherence to preventive measures against COVID-19.

Knowledge, attitudes, and practices associated with frequent influenza vaccination among healthcare personnel in Peru, 2016─2018

IntroductionDespite a government-subsidized vaccination program, healthcare personnel (HCP) influenza vaccination uptake remains low in Peru. Using three years of cross-sectional surveys and an additional five years of prior vaccination history of HCP in Peru, we explored HCP knowledge, attitudes, and practices (KAP) of influenza illness and its impact on vaccination frequency. MethodsIn 2016, the Estudio Vacuna de Influenza Peru (VIP) cohort was initiated in Lima, Peru, which collected information about HCP KAP and influenza vaccination history from 2011─2018. HCP were classified by their 8-year influenza vaccination history as never (0 years), infrequently (1─4 years), or frequently (5─8 years) vaccinated. Logistic regression models were used to describe KAP associated with frequent compared to infrequent influenza vaccination, adjusted for each HCP’s healthcare workplace, age, sex, preexisting medical conditions, occupation, and length of time providing direct patient care. ResultsFrom 2016─2018, 5131 HCP were recruited and 3120 fully enrolled in VIP; 2782 consistently reported influenza vaccination status and became our analytic sample. From 2011─2018, 14.3% of HCP never, 61.4% infrequently, and 24.4% frequently received influenza vaccines. Compared to HCP who were infrequently vaccinated, frequently vaccinated HCP were more likely to believe they were susceptible to influenza (adjusted odds ratio [aOR]:1.49, 95% confidence interval [CI]:1.22─1.82), perceived vaccination to be effective (aOR:1.92, 95%CI:1.59─2.32), were knowledgeable about influenza and vaccination (aOR:1.37, 95%CI:1.06─1.77), and believed vaccination had emotional benefits like reduced regret or anger if they became ill with influenza (aOR:1.96, 95%CI:1.60─2.42). HCP who reported vaccination barriers like not having time or a convenient place to receive vaccines had reduced odds of frequent vaccination (aOR:0.74, 95%CI:0.61─0.89) compared to those without reported barriers. ConclusionFew HCP frequently received influenza vaccines during an eight-year period. To increase HCP influenza vaccination in middle-income settings like Peru, campaigns could strengthen influenza risk perception, vaccine knowledge, and accessibility.

Influenza vaccine uptake among children and older adults in China: a secondary analysis of a quasi-experimental study

BackgroundInfluenza vaccination is the key to prevent influenza-related disease, especially among high-risk populations. However, influenza vaccine uptake in China is low. This secondary analysis of a quasi-experimental trial aimed to understand factors associated with influenza vaccine uptake among children and older people stratified by funding context.MethodsA total of 225 children (aged 0.5-8 years) and 225 older people (aged 60 years or above) were recruited from three clinics (rural, suburban and urban) in Guangdong Province. Participants were allocated into two groups based on funding contexts: a self-paid group (N = 150, 75 children and 75 older adults) in which participants paid full price for their vaccination; and a subsidized group (N = 300, 150 children and 150 older adults) in which varying levels of financial support was provided. Univariate and multivariable logistic regressions were conducted stratified by funding contexts.ResultsOverall, 75.0% (225/300) of participants in the subsidized group and 36.7% (55/150) in the self-paid group got vaccinated. Older adults had lower vaccination rates than children in both funding groups, while both age groups showed much higher uptake in the subsidized group than in the self-paid group (aOR = 5.96, 95% CI: 3.77–9.42, p = 0.001). In the self-paid group, having prior influenza vaccination history of children (aOR:2.61, 95%CI: 1.06–6.42) or older people (aOR:4.76, 95%CI: 1.08–20.90) was associated with increased influenza vaccine uptake compared to those who had no prior vaccination experiences in the family. While in the subsidized group, participants who got married or lived with partners (aOR = 0.32, 0.10–0.98) had lower vaccination uptake than single ones. Trust in providers’ advice (aOR = 4.95, 95%CI:1.99, 12.43), perceived effectiveness of the vaccine (aOR: 12.18, 95%CI: 5.21–28.50), and experienced influenza-like illnesses in the family in the past year (aOR = 46.52, 4.10, 533.78) were associated with higher vaccine uptake.ConclusionsOlder people had suboptimal vaccine uptake compared to children in both contexts and need more attention to enhance influenza vaccination. Tailoring interventions to different vaccine funding contexts may help improve influenza vaccination: In self-paid context, motivating people to accept their first ever influenza vaccination may be a promising strategy. In subsidized context, improving public confidence in vaccine effectiveness and providers’ advice would be useful.

Factors influencing scar formation following Bacille Calmette-Guérin (BCG) vaccination

The prevalence of scar formation following Bacille Calmette-Guérin (BCG) vaccination varies globally. The beneficial off-target effects of BCG are proposed to be stronger amongst children who develop a BCG scar. Within an international randomised trial (‘BCG vaccination to reduce the impact of coronavirus disease 2019 (COVID-19) in healthcare workers’; BRACE Trial), this nested prospective cohort study assessed the prevalence of and factors influencing scar formation, as well as participant perception of BCG scarring 12 months following vaccination . Amongst 3071 BCG-recipients, 2341 (76%) developed a BCG scar. Scar prevalence was lowest in Spain and highest in UK. Absence of post-injection wheal (OR 0.4, 95%CI 0.2–0.9), BCG revaccination (OR 1.7, 95%CI 1.3–2.0), female sex (OR 2.0, 95%CI 1.7–2.4), older age (OR 0.4, 95%CI 0.4–0.5) and study country (Brazil OR 1.6, 95%CI 1.3–2.0) influenced BCG scar prevalence. Of the 2341 participants with a BCG scar, 1806 (77%) did not mind having the scar. Participants more likely to not mind were those in Brazil, males and those with a prior BCG vaccination history. The majority (96%) did not regret having the vaccine.Both vaccination-related (amenable to optimisation) and individual-related factors affected BCG scar prevalence 12 months following BCG vaccination of adults, with implications for maximising the effectiveness of BCG vaccination.

Field Performance of a Rapid Test to Detect Progressive, Regressive, and Abortive Feline Leukemia Virus Infections in Domestic Cats in Australia and Germany.

Different feline leukemia virus (FeLV) infection outcomes are possible in cats following natural exposure, such as progressive infections (persistent viremia), regressive infections (transient or no viremia followed by proviral persistence) and abortive infections (presence of only antibodies). Laboratory-based testing is currently required for categorization of infection outcomes in cats. The aim of this study was to evaluate the field performance of a novel, rapid, combination point-of-care (PoC) test kit commercially available in Europe (v-RetroFel®Ag/Ab; 2020-2021 version) to determine different FeLV infection outcomes by concurrent detection of FeLV antigen (p27) and antibodies against FeLV transmembrane envelope protein (p15E). A secondary aim was to evaluate the performance of the same test kit (v-RetroFel®FIV) to determine positive/negative feline immunodeficiency virus (FIV) infection status by the detection of antibodies to FIV capsid protein (p24) and transmembrane glycoprotein (gp40). Two cohorts of domestic cats were recruited and tested with v-RetroFel® using plasma or serum, including cats in Australia (n = 200) and cats in Germany (n = 170). Results from p27 antigen PoC testing, proviral DNA PCR, and neutralizing antibody testing or testing for antibodies against non-glycosylated surface unit envelope protein (p45) were used to assign cats to groups according to different FeLV infection outcomes. Testing with a laboratory-based FeLV p15E antibody ELISA was also performed for comparison. In the first cohort, v-RetroFel®Ag/Ab correctly identified 89% (109/122) FeLV-unexposed cats and 91% (21/23) progressive infections, but no regressive (0/23) or abortive (0/32) infections. In the second cohort, v-RetroFel®Ag/Ab correctly identified 94% (148/158) FeLV-unexposed cats and 100% (4/4) progressive infections, but no regressive (0/2) and only 17% (1/6) abortive infections. There was test agreement between v-RetroFel®Ab and the p15E laboratory ELISA in 58.9% of samples. As a secondary outcome of this study, the sensitivity and specificity of v-RetroFel®FIV testing in cohort 1 were 94.7% (18/19) and 98.3% (178/181), and in cohort 2, 30.0% (3/10) and 100.0% (160/160), respectively. Prior history of FIV vaccination did not produce any false-positive FIV results. In conclusion, v-RetroFel®Ag/Ab (2020-2021 version) was unable to accurately determine different FeLV infection outcomes in the field. Improvements of the test prior to application to field samples are required.

1934. Association between Receipt of COVID-19, Influenza, and Pneumococcal Vaccination

Abstract Background Whether receipt of COVID-19 vaccine associates with receipt of other routinely-recommended adult vaccines such as, influenza and pneumococcal vaccines is not well described. We evaluated this relationship in a population of adults who were hospitalized for acute respiratory infection (ARI). *Odds ratio describing odds of receiving at least one COVID-19 vaccine (vs not) by influenza vaccination status adjusted for race, employment status, chronic cardiac diseases, cancer, solid organ transplant, and chronic kidney disease.**Odds ratio describing odds of receiving at least one COVID-19 vaccine (vs not) by pneumococcal vaccination status adjusted for race and chronic kidney disease. Methods We enrolled adults (≥ 18 years of age) who were hospitalized at Emory University Hospital and Emory University Hospital Midtown with symptoms consistent with ARI. Participants were interviewed and medical records abstracted to gather demographic information, including social behaviors during the pandemic, medical history, and prior vaccination history (i.e., COVID-19, influenza, and pneumococcal). Using two separate logistic regression analyses, we determined the association between i) receipt of influenza vaccine in the prior year among adults ≥ 18 years and ii) receipt of any pneumococcal vaccine in the prior 5 years among adults ≥ 65 years on the receipt of at least one COVID-19 vaccine≥ 14 days prior to admission. Adjusted models included demographic information (e.g., age, sex, race/ethnicity, employment status), social behaviors, and history of chronic medical conditions. Results Overall, 1056 participants were enrolled and had vaccination records available. Of whom, 509/1056 (48.2%) had received at least one dose of COVID-19 vaccine. Adults ≥ 18 years who received influenza vaccine were more likely to have received ≥1 dose of COVID-19 vaccine compared to those who did not (267/373 [71.6%] vs 242/683 [35.4%] P=&amp;lt; .0001; adjusted odds ratio [OR]: 3.3 [95%CI: 2.4, 4.4]). Similarly, adults ≥65 years who received pneumococcal vaccine were more likely to have received ≥ 1 dose of COVID-19 vaccine compared to those who did not (195/257 [75.9%] vs 41/84 [48.8%] P=&amp;lt; .0001; adjusted odds ratio [OR]: 3.0 [95%CI: 1.8, 5.1]). Conclusion In this study of adults hospitalized for ARI, receipt of influenza and pneumococcal vaccination strongly correlated with receipt of COVID-19 vaccination. Continued efforts are needed to reach adults who remain hesitant to not only receive COVID-19 vaccines, but also other vaccines that lessen the burden of respiratory illness. Disclosures Laura A. Puzniak, PhD. MPH, Merck &amp; Co., Inc.: Stocks/Bonds|Pfizer, Inc.: Stocks/Bonds Robin Hubler, MS, Pfizer Inc.: Employee|Pfizer Inc.: Stocks/Bonds Srinivas Valluri, PhD, Pfizer: Employee|Pfizer: Stocks/Bonds Benjamin Lopman, PhD, Epidemiological Research and Methods, LLC: Advisor/Consultant Satoshi Kamidani, MD, NIH: His institution (Emory University) receives funds from Pfizer for his work as a co-investigator on clinical trials of Pfizer COVID-19 vaccine.|Pfizer: His institution (Emory University) receives funds from Pfizer for his work as a co-investigator on clinical trials of Pfizer COVID-19 vaccine. Christina A. Rostad, MD, BioFire Inc, GSK, MedImmune, Micron, Merck, Novavax, PaxVax, Pfizer, Regeneron, Sanofi-Pasteur.: Grant/Research Support|Meissa Vaccines, Inc.: Co-inventor of RSV vaccine technology licensed to Meissa Vaccines, Inc.|NIH (Funding from NIH to conduct clinical trials of Moderna and Janssen COVID-19 vaccines): Grant/Research Support John M. McLaughlin, PhD, Pfizer: Employee|Pfizer: Stocks/Bonds Evan J. Anderson, MD, GSK: Advisor/Consultant|GSK: Grant/Research Support|Janssen: Advisor/Consultant|Janssen: Grant/Research Support|Kentucky Bioprocessing, Inc: Data Safety Monitoring Board|MedImmune: Grant/Research Support|Medscape: Advisor/Consultant|Merck: Grant/Research Support|Micron: Grant/Research Support|NIH: Funding from NIH to conduct clinical trials of Moderna and Janssen COVID-19 vaccines|PaxVax: Grant/Research Support|Pfizer: Advisor/Consultant|Pfizer: Grant/Research Support|Regeneron: Grant/Research Support|Sanofi Pasteur: Advisor/Consultant|Sanofi Pasteur: Grant/Research Support|Sanofi Pasteur: Data Adjudication and Data Safety Monitoring Boards|WCG and ACI Clinical: Data Adjudication Board.

639. Vaccination in Kidney Transplant Candidates

Abstract Background Kidney transplant (KT) candidates have historically low immunization rates against recommended vaccines. A retrospective study of KT candidates was conducted to assess contemporary vaccination rates and vaccine uptake during pre-transplant evaluation. Methods All KT candidates ≥ 18 years referred to Transplant Infectious Disease Clinic for pre-transplant evaluation between January 1, 2020 and August 31, 2020 were retrospectively studied for history of prior vaccination against Tdap, 13 valent pneumococcal conjugate vaccine (PCV13), 23 valent pneumococcal polysaccharide vaccine (PPSV23), Hepatitis A and B (using Hepatitis A total IgG and Hepatitis B surface antibodies as surrogate markers) and recombinant zoster vaccine (RZV). Seropositivity (as a marker of immunity) against measles, mumps, rubella and varicella was also assessed. Results 109 KT candidates were evaluated (tables 1 &amp; 2). Rates of prior vaccination against Tdap, PCV13 and PPSV23 were 33%, 58%, and 67%. Only 5 (8%) of 61 patients ≥ 50 years of age had received 2 doses of RZV. Thirty (28%) had positive Hepatitis A total IgG and 72 (66%) patients had a positive Hepatitis B surface antibody. Among 37 patients with negative Hepatitis B surface antibody, most had received at least one dose of Hepatitis B vaccine (five were non responders, 19 had had initiated the vaccine series and one had waning antibody response). 79-96% patients had immunity against measles, mumps, rubella and varicella. Patients ≥ 50 years (vs under 50 years) had numerically higher immunization rates against PCV13 and PPSV23 (67% vs 46% and 74% vs 58%) and higher rates of immunity against measles, mumps, rubella and varicella (95% vs 73%; 85% vs 69%, 95% vs 81% and 100% vs 92% respectively). Dialysis patients had a higher Hepatitis B surface antibody compared to non-dialysis patients (78% vs 39%). Only 6 of 109 patients were fully immunized. Among 103 vaccine eligible patients, 99 (96%) agreed to get vaccinated. Table 1Baseline characteristics of kidney transplant candidates Table 2 Vaccination in kidney transplant candidates Conclusion KT candidates have low rates of prior immunization against Tdap, PCV13, PPSV23, Hepatitis A and B and RZV but high rates of serological immunity against measles, mumps, rubella and varicella. The vaccine uptake during pre-transplant evaluation was high and it provides an unique opportunity to improve immunization in this population. Disclosures All Authors: No reported disclosures.

Serological responses to the MVA-based JYNNEOS monkeypox vaccine in a cohort of participants from the Democratic Republic of Congo

The current worldwide monkepox outbreak has reaffirmed the continued threat monkeypox virus (MPXV) poses to public health. JYNNEOS, a Modified Vaccinia Ankara (MVA)-based live, non-replicating vaccine, was recently approved for monkeypox prevention for adults at high risk of MPXV infection in the United States. Although the safety and immunogenicity of JYNNEOS have been examined previously, the clinical cohorts studied largely derive from regions where MPXV does not typically circulate. In this study, we assess the quality and longevity of serological responses to two doses of JYNNEOS vaccine in a large cohort of healthcare workers from the Democratic Republic of Congo (DRC). We show that JYNNEOS elicits a strong orthopoxvirus (OPXV)-specific antibody response in participants that peaks around day 42, or 2 weeks after the second vaccine dose. Participants with no prior history of smallpox vaccination or exposure have lower baseline antibody levels, but experience a similar fold-rise in antibody titers by day 42 as those with a prior history of vaccination. Both previously naïve and vaccinated participants generate vaccinia virus and MPXV-neutralizing antibody in response to JYNNEOS vaccination. Finally, even though total OPXV-specific IgG titers and neutralizing antibody titers declined from their peak and returned close to baseline levels by the 2-year mark, most participants remain IgG seropositive at the 2-year timepoint. Taken together, our data demonstrates that JYNNEOS vaccination triggers potent OPXV neutralizing antibody responses in a cohort of healthcare workers in DRC, a monkeypox-endemic region. MPXV vaccination with JYNNEOS may help ameliorate the disease and economic burden associated with monkeypox and combat potential outbreaks in areas with active virus circulation.

Building on a Strong Foundation to Address a New Era to Help Protect Against Pneumococcal Disease

Antoni Torres, Respiratory Intensive Care Unit, Department of Pneumology and Respiratory Allergy, Hospital Clinic of Barcelona, University of Barcelona, Spain, opened the symposium, noting that pneumococcal conjugate vaccines (PCV) have reduced pneumococcal disease through direct and indirect effects. However, the burden of pneumococcal disease remains substantial in adults, supporting the importance of further reducing vaccine-preventable disease and its impact on healthcare resource utilisation and public health. Mário Ramirez, Faculty of Medicine, University of Lisbon, Portugal, and Molecular Microbiology and Infection Laboratory, Institute of Molecular Medicine, University of Lisbon, Portugal, reviewed the changing serotype epidemiology of pneumococcal disease in Europe, and described important differences between pneumococcal polysaccharide vaccines and PCVs. He detailed the dramatic direct impact of PCVs in children in decreasing the burden of vaccine-type (VT) pneumococcal disease, as well as indirect effects in unvaccinated populations, particularly adults. Residual VT-disease and increases in non-PCV13 disease underscore the need for additional disease coverage that may be afforded by higher-valent PCVs. Charles Feldman, Department of Internal Medicine, University of the Witwatersrand, Johannesburg, South Africa, reviewed the considerable worldwide burden of lower respiratory tract infections (LRTI), including pneumococcal pneumonia. He noted that indirect effects in adults may be suboptimal, and herd effects may have reached their limit. Feldman described adult populations that should be prioritised for pneumococcal vaccination based on risk factors, and stressed the importance of a comprehensive approach to increase adult vaccination. Finally, Wendy Watson, Vaccines Clinical Research, Pfizer, Collegeville, USA, described the adult PCV20 clinical development programme, emphasising that it was built on the well-established PCV13 platform. In the Phase III clinical trial programme, PCV20 was well tolerated, with a safety profile similar to PCV13, regardless of prior pneumococcal vaccination history. Importantly, it was immunogenic across all ages studied and in those with chronic medical conditions. Wendy Watson concluded that PCV20 has the potential to simplify adult vaccination and help reduce the burden of adult pneumococcal disease.

Measles seroprevalence in persons over one year of age in Chandigarh, India

ABSTRACT Measles continues to result in focal outbreaks in India, despite over three decades of universal infant vaccination. The aims of this study were to examine measles immunity in the population of Chandigarh, India, and to compare immunity by vaccination vs. natural infection. In a cross-sectional study of individuals 1–60 years selected from 30 communities within Chandigarh during 2017–2018, measles immunity was assessed using serological surveys. Seropositivity was compared across demographic groups, and by prior history of vaccination and natural history of infection. Among those 1–20 years old, measles seropositivity, and histories of measles vaccination or prior measles diagnosis were separately assessed as outcomes in logistic regression models, with demographic factors as independent variables. Among 1690 participants, 94% were seropositive, and 6% had borderline or negative antibody levels. Of those positive, 30% had prior vaccination, 16% had a history of natural infection, and 54% had an unknown history. Over 50% of individuals among those >20 years old, had unknown history of immunity. In the multivariable regression models, vaccination was more common in younger ages (P < .0001), and in males compared to females (P = .0220), and in those with more education (P < .0001). The majority of the population was seropositive, and seropositivity increased with age. Older age groups were more likely to be protected because of previous natural infection, whereas younger age groups were protected by vaccination. There was inequity in vaccination coverage by gender, and maternal education status.