History Of Prior Infection Research Articles

Risk Factors for Delayed Treatment of Gonorrhea and Chlamydia in Active-Duty Service Members.

Sexually transmitted infections including gonorrhea and chlamydia are common in the active-duty military population, with historically higher rates than their civilian counterparts. Prevention and screening are 2 of the main strategies used to reduce the chronic medical complications and costs associated with untreated gonorrhea and chlamydia; however, there is little information in the literature regarding treatment time after a positive screening. To our knowledge, there has not yet been a study regarding delayed treatment of gonorrhea and chlamydia in the active-duty population. We performed a population-based retrospective observational study on active-duty service members (ADSMs) diagnosed with gonorrhea and chlamydia from 2010-2019. Statistical analysis was performed to determine differences in treatment times for key demographics. This study was reviewed and approved by the Brooke Army Medical Center Institutional Review Board. Average treatment time was 3.5 days for individuals with chlamydia and 5 days for those with gonorrhea. Treatment within 2 weeks was met for 94% of people diagnosed with chlamydia and 91% of people diagnosed with gonorrhea. Delay in treatment times for chlamydia were seen in men, ages 25-34, full-time active-duty service members, those with a history of prior infection, and soldiers in the Army. Gonorrhea treatment times were delayed in men, members of the Coast Guard, ages 35-44, and those with a history of prior infection. Significant differences in treatment time were seen based on sex, age, branch of service, rank, and history of prior infection.

Validation of clinical risk tools for recurrent Clostridioides difficile infection.

We sought to validate available tools for predicting recurrent C. difficile infection (CDI) including recurrence risk scores (by Larrainzar-Coghen, Reveles, D'Agostino, Cobo, and Eyre et al) alongside consensus guidelines risk criteria, the leading severity score (ATLAS), and PCR cycle threshold (as marker of fecal organism burden) using electronic medical records. Retrospective cohort study validating previously described tools. Tertiary care academic hospital. Hospitalized adult patients with CDI at University of Virginia Medical Center. Risk scores were calculated within ±48 hours of index CDI diagnosis using a large retrospective cohort of 1,519 inpatient infections spanning 7 years and compared using area under the receiver operating characteristic curve (AUROC) and the DeLong test. Recurrent CDI events (defined as a repeat positive test or symptom relapse within 60 days requiring retreatment) were confirmed by clinician chart review. Reveles et al tool achieved the highest AUROC of 0.523 (and 0.537 among a subcohort of 1,230 patients with their first occurrence of CDI), which was not substantially better than other tools including the current IDSA/SHEA C. difficile guidelines or PCR cycle threshold (AUROC: 0.564), regardless of prior infection history. All tools performed poorly for predicting recurrent C. difficile infection (AUROC range: 0.488-0.564), especially among patients with a prior history of infection (AUROC range: 0.436-0.591). Future studies may benefit from considering novel biomarkers and/or higher-dimensional models that could augment or replace existing tools that underperform.

Protection against symptomatic dengue infection by neutralizing antibodies varies by infection history and infecting serotype

Dengue viruses (DENV1–4) are the most prevalent arboviruses in humans and a major public health concern. Understanding immune mechanisms that modulate DENV infection outcome is critical for vaccine development. Neutralizing antibodies (nAbs) are an essential component of the protective immune response, yet their measurement often relies on a single cellular substrate and partially mature virions, which does not capture the full breadth of neutralizing activity and may lead to biased estimations of nAb potency. Here, we analyze 125 samples collected after one or more DENV infections but prior to subsequent symptomatic or inapparent DENV1, DENV2, or DENV3 infections from a long-standing pediatric cohort study in Nicaragua. By assessing nAb responses using Vero cells with or without DC-SIGN and with mature or partially mature virions, we find that nAb potency and the protective NT50 cutoff are greatly influenced by cell substrate and virion maturation state. Additionally, the correlation between nAb titer and protection from disease depends on prior infection history and infecting serotype. Finally, we uncover variations in nAb composition that contribute to protection from symptomatic infection differently after primary and secondary prior infection. These findings have important implications for identifying antibody correlates of protection for vaccines and natural infections.

Roseomonas Mucosa Bacteremia in an Immunocompetent Child

We report a case of bacteremia associated with Roseomonas mucosa isolated from an immunocompetent pediatric patient with no prior history of infection and bacteremia.

The Value of in-vitro Local Ceftriaxone Interrupted Irrigation for Soft Tissue Autograft in Arthroscopic ACL Reconstruction

Background: Postoperative septic arthritis of the knee joint is an uncommon complication with serious consequences following anterior cruciate ligament reconstruction (ACLR). Systemic antibiotics received preoperatively and presoaking the soft tissue autograft with antibiotics result in a lower infection rate. Preoperative intravenous antibiotics may not be sufficient enough to reach minimum inhibitory concentration (MIC) levels due to poor vascularity of hamstring tendons in addition the harvested graft is prone to infection from skin flora. Aim of the study: To assess the efficacy of local antibiotic (ceftriaxone drug 1g.) solution diluted in (500 mL 0.9% sodium chloride N/S) for invitro interrupted irrigation of harvested soft tissue ACL graft as prophylaxis in reducing the infection rate during knee joint arthroscopic procedure. Patients and Methods: A Prospective comparative study of forty patients fit for arthroscopic anterior cruciate ligament reconstruction were enrolled in the study. The timeline period from April 2022 to July 2023.patients divided into (group A), twenty patients (received local ceftriaxone irrigation 1gm. solution diluted in 500 mL 0.9% NaCl for presoaking soft tissue autograft) and (Group B), twenty patients received (plain NaCl 0.9% ) only for irrigation of harvested graft. All patients in both groups received intravenous ceftriaxone at time of induction of anesthesia. Patients with history of injury more than 2years, open procedure, intravenous drug abuse, alcoholism steroid use, revision cases, and a prior history of infection in the knee were excluded from the study. Patients were followed postoperatively by clinical, laboratory, and imaging studies. The chi-square test was used for the comparison of categorical data. A student T-test and ANOVA were conducted to demonstrate the differences in postoperative inflammatory markers. Results: Presoaking of soft tissue autograft with ceftriaxone was performed in 20 patients (the study group), while 20 patients (the control group) were soaked only with plain N/S. In the control group, two patients (10%) developed postoperative infection after 2 weeks postoperatively, while no case developed infection in the study group. There was no statistically significant difference (p >0.05) between the study and control groups in terms of demographic characteristics, type of graft (p = 0.34), associated arthroscopic procedure (p = 0.35), and Lysholm score (p = 0.58). In the study group, there was a significant decrease in ESR (P = 0.01) after 4 weeks, Total lymphocyte count (p = 0.04), and Polymorphonuclear (p = 0.03) after 6 weeks postoperatively. Conclusion: Presoaking of hamstring autograft with ceftriaxone intraoperative may be alternative for other antibiotics in reducing rate of infection following arthroscopic anterior cruciate ligament reconstruction.

Class switch towards spike protein-specific IgG4 antibodies after SARS-CoV-2 mRNA vaccination depends on prior infection history

Vaccinations against SARS-CoV-2 reduce the risk of developing serious COVID-19 disease. Monitoring spike-specific IgG subclass levels after vaccinations may provide additional information on SARS-CoV-2 specific humoral immune response. Here, we examined the presence and levels of spike-specific IgG antibody subclasses in health-care coworkers vaccinated with vector- (Sputnik, AstraZeneca) or mRNA-based (Pfizer-BioNTech, Moderna) vaccines against SARS-CoV-2 and in unvaccinated COVID-19 patients. We found that vector-based vaccines elicited lower total spike-specific IgG levels than mRNA vaccines. The pattern of spike-specific IgG subclasses in individuals infected before mRNA vaccinations resembled that of vector-vaccinated subjects or unvaccinated COVID-19 patients. However, the pattern of mRNA-vaccinated individuals without SARS-CoV-2 preinfection showed a markedly different pattern. In addition to IgG1 and IgG3 subclasses presented in all groups, a switch towards distal IgG subclasses (spike-specific IgG4 and IgG2) appeared almost exclusively in individuals who received only mRNA vaccines or were infected after mRNA vaccinations. In these subjects, the magnitude of the spike-specific IgG4 response was comparable to that of the spike-specific IgG1 response. These data suggest that the priming of the immune system either by natural SARS-CoV-2 infection or by vector- or mRNA-based vaccinations has an important impact on the characteristics of the developed specific humoral immunity.

Comparing SARS-CoV-2 neutralizing antibody levels in convalescent unvaccinated, convalescent vaccinated, and naive vaccinated subjects

BackgroundSevere acute respiratory syndrome coronavirus 2 (SARS-CoV-2) emerged in December 2019 and spread rapidly. The purpose of this study was to compare neutralizing antibodies (NAbs) following the original booster vaccine in convalescent and naive vaccinated individuals and in a third comparison group consisting of unvaccinated convalescent plasma donors. MethodsWe assessed NAbs before and 2 months after a booster vaccine in 68 adults who had completed the initial vaccine series for SARS-CoV-2. Of these subjects, 58 had no history of prior infection (naïve vaccinated group) and 10 had been infected with SARS-COV-2 prior to the completing the first vaccine series (convalescent vaccinated group). A third comparison group included unvaccinated convalescent plasma donors (n = 55) from an earlier study with NAbs assessed approximately 2 months after a positive test for SARS-CoV-2. ResultsPrior to the booster, convalescent vaccinated subjects had higher NAbs compared to naive vaccinated subjects (p = 0.02). Two months following the booster, NAbs increased in both vaccinated groups. The naive vaccinated group increased more than the convalescent vaccinated group (p = 0.02). NAbs in the naive vaccinated group were almost four times higher than NAbs in the 55 unvaccinated subjects, while the convalescent vaccinated group had levels 2.5 times higher p < 0.01. ConclusionNAbs in both vaccinated/boosted groups were significantly higher than in the convalescent unvaccinated group (p < 0.01). Our data indicates that subjects with a single infection with SARS-CoV-2 did not have the same levels of neutralizing antibodies that we observed in subjects who were either in the convalescent vaccinated or the naive vaccinated groups.

Adolescent COVID-19 Cases During the SARS-CoV-2 Delta and Omicron Variant Surges in Kentucky: Association With Vaccination and Prior Infection

PurposeEffectiveness of COVID-19 mRNA vaccines is influenced by SARS-CoV-2 variant and history of prior infection. Data regarding protection against SARS-CoV-2 infection among adolescents, accounting for prior infection and time since vaccination, are limited. MethodsSARS-CoV-2 testing and immunization data from the Kentucky Electronic Disease Surveillance System and the Kentucky Immunization Registry, August–September 2021 (Delta predominance) and January 2022 (Omicron Predominance) among adolescents aged 12–17 years, were used to assess association of SARS-CoV-2 infection with mRNA vaccination and prior SARS-CoV-2 infection. Estimated protection was derived from prevalence ratios ([1-PR] × 100%). ResultsDuring Delta predominance, 89,736 tested adolescents were evaluated. Completion of primary series (second dose of mRNA vaccine ≥ 14 days prior to testing) and history of prior infection (> 90 days prior to testing) were both protective against SARS-CoV-2 infection (primary series: 81%, 95% confidence interval [CI] 79.7–82.3; prior infection: 66%, 95% CI 62.0–69.6). Prior infection plus primary series provided the greatest protection (92.3%, 95% CI 88.0–95.1). During Omicron predominance, 67,331 tested adolescents were evaluated. Primary series alone provided no benefit against SARS-CoV-2 infection after 90 days; prior infection was protective for up to one year (24.2%, 95% CI 17.2–30.7). Prior infection plus booster vaccination provided the greatest protection against infection (82.4%, 95% CI 62.1–91.8). DiscussionStrength and duration of protection against infection provided by COVID-19 vaccination and prior SARS-CoV-2 infection differed by variant. Vaccination provided additional benefit to the protection offered by prior infection alone. Remaining up to date with vaccination is recommended for all adolescents regardless of infection history.

Defining parameters that influence susceptibility and protection to murine respiratory beta-coronavirus MHV-1 infection

Abstract Patients infected with SARS-CoV-2 can experience variable susceptibility and sepsis-like immune dysfunction. Also, patients with comorbidities such as previous septic events are more likely to be hospitalized and succumb to COVID19 complications. However, the extent to which respiratory beta-coronavirus pathology is dose dependent and produces sepsis-like dysregulation in an experimental murine model are not completely defined. We utilized an established SARS-like murine model by infecting Murine Hepatitis Virus 1 (MHV-1) susceptible C3H/HeJ mice intranasally and analyzed responses over time after primary and/or secondary challenges. Immunologically naïve C3H mice undergo pathological changes defined by dose-dependent changes in disease severity and lung infiltrate/edema. MHV-infected mice also experience sepsis-like lymphopenia and cytokine dysregulation in the blood. Importantly, a low/surviving dose (5×10 2PFU) was identified that yielded no morbidity/mortality after infection of C3H hosts. However, this low dose provides antibody dependent but not CD4/CD8 circulatory T cell dependent protection against a lethal high dose MHV-1 re-challenge. In addition, while C3H hosts with history of prior infections were more resistant, C3H mice that survived surgical sepsis showed increased susceptibility to MHV-1 infection over their surgical sham controls. Together, these data define how infection dose, immunological status, and/or comorbidities influence outcome of primary and secondary beta-coronavirus infections in highly susceptible hosts. Supported by grants from NIH (R35GM134880, T32AI007511)

Association of Treatment With Nirmatrelvir and the Risk of Post–COVID-19 Condition

Post-COVID-19 condition (PCC), also known as long COVID, affects many individuals. Prevention of PCC is an urgent public health priority. To examine whether treatment with nirmatrelvir in the acute phase of COVID-19 is associated with reduced risk of PCC. This cohort study used the health care databases of the US Department of Veterans Affairs (VA) to identify patients who had a SARS-CoV-2 positive test result between January 3, 2022, and December 31, 2022, who were not hospitalized on the day of the positive test result, who had at least 1 risk factor for progression to severe COVID-19 illness, and who had survived the first 30 days after SARS-CoV-2 diagnosis. Those who were treated with oral nirmatrelvir within 5 days after the positive test (n = 35 717) and those who received no COVID-19 antiviral or antibody treatment during the acute phase of SARS-CoV-2 infection (control group, n = 246 076) were identified. Treatment with nirmatrelvir or receipt of no COVID-19 antiviral or antibody treatment based on prescription records. Inverse probability weighted survival models were used to estimate the association of nirmatrelvir (vs control) with post-acute death, post-acute hospitalization, and a prespecified panel of 13 post-acute COVID-19 sequelae (components of PCC) and reported in relative scale as relative risk (RR) or hazard ratio (HR) and in absolute scale as absolute risk reduction in percentage at 180 days (ARR). A total of 281 793 patients (mean [SD] age, 61.99 [14.96]; 242 383 [86.01%] male) who had a positive SARS-CoV-2 test result and had at least 1 risk factor for progression to severe COVID-19 illness were studied. Among them, 246 076 received no COVID-19 antiviral or antibody treatment during the acute phase of SARS-CoV-2 infection, and 35 717 received oral nirmatrelvir within 5 days after the positive SARS-CoV-2 test result. Compared with the control group, nirmatrelvir was associated with reduced risk of PCC (RR, 0.74; 95% CI, 0.72-0.77; ARR, 4.51%; 95% CI, 4.01-4.99), including reduced risk of 10 of 13 post-acute sequelae (components of PCC) in the cardiovascular system (dysrhythmia and ischemic heart disease), coagulation and hematologic disorders (pulmonary embolism and deep vein thrombosis), fatigue and malaise, acute kidney disease, muscle pain, neurologic system (neurocognitive impairment and dysautonomia), and shortness of breath. Nirmatrelvir was also associated with reduced risk of post-acute death (HR, 0.53; 95% CI, 0.46-0.61); ARR, 0.65%; 95% CI, 0.54-0.77), and post-acute hospitalization (HR, 0.76; 95% CI, 0.73-0.80; ARR, 1.72%; 95% CI, 1.42-2.01). Nirmatrelvir was associated with reduced risk of PCC in people who were unvaccinated, vaccinated, and boosted, and in people with primary SARS-CoV-2 infection and reinfection. This cohort study found that in people with SARS-CoV-2 infection who had at least 1 risk factor for progression to severe disease, treatment with nirmatrelvir within 5 days of a positive SARS-CoV-2 test result was associated with reduced risk of PCC across the risk spectrum in this cohort and regardless of vaccination status and history of prior infection; the totality of findings suggests that treatment with nirmatrelvir during the acute phase of COVID-19 may reduce the risk of post-acute adverse health outcomes.

Syphilitic balanitis of Follmann in a patient with a history of previous infection.

We report a case of syphilitic balanitis of Follmann arising in a man with a history of prior infection with syphilis. Few cases have been described in the literature. In our case, a man with history of multiple unprotected sexual contacts presented with erosive balanitis and painless inguinal bilateral lymphadenopathy. All tests for sexually transmitted infections (STIs) performed were negative with the exception of serology for syphilis. We made the diagnosis of syphilitic balanitis of Follmann that was confirmed by prompt resolution after treatment.

SARS-CoV-2 antibodies among health care workers from a children's hospital.

Introduction. In Argentina, health care workers have been the first ones to receive the COVID-19 vaccine, but there are still few data on the production of anti-S IgG antibodies. Objectives. To assess specific IgG against the SARS-CoV-2 spike protein (anti-S IgG) after the vaccination of health care workers from a children's hospital. To explore the association between the presence of these antibodies, age, and history of prior infection. Population and methods. Cross-sectional study in 193 workers who received both doses of the two- component Sputnik V vaccine. The anti-S IgG antibody titer was measured and age, history of prior SARS-CoV-2 infection, and date of vaccination were recorded. Results. Anti-S IgG antibodies were produced in 98.6% of the subjects. The titer was higher in those with prior infection (p < 0.001), but no relationship was established with subjects' age. Conclusion. We provide data on post-vaccination production of IgG anti-S antibodies among health care workers from a children's hospital and explore some predictors.

Age-adjusted impact of prior COVID-19 on SARS-CoV-2 mRNA vaccine response.

More people with a history of prior infection are receiving SARS-CoV-2 vaccines. Understanding the level of protection granted by 'hybrid immunity', the combined response of infection- and vaccine-induced immunity, may impact vaccination strategies through tailored dosing. A total of 36 infected ('prior infection') and 33 SARS-CoV-2 'naïve' individuals participated. Participants provided sera six months after completing a round of BNT162b2 vaccination, to be processed for anti-spike antibody measurements and the receptor binding domain-ACE2 binding inhibition assays. The relationships between antibody titer, groups and age were explored. Anti-spike antibody titers at 6 months post-vaccination were significantly higher, reaching 13- to 17-fold, in the 'prior infection' group. Semi-log regression models showed that participants with 'prior infection' demonstrated higher antibody titer compared with the 'naïve' even after adjusting for age. The enhancement in antibody titer attributable to positive infection history increased from 8.9- to 9.4- fold at age 30 to 19- to 32-fold at age 60. Sera from the 'prior infection' group showed higher inhibition capacity against all six analyzed strains, including the Omicron variant. Prior COVID-19 led to establishing enhanced humoral immunity at 6 months after vaccination. Antibody fold-difference attributed to positive COVID-19 history increased with age, possibly because older individuals are prone to symptomatic infection accompanied by potentiated immune responses. While still pending any modifications of dosing recommendations (i.e. reduced doses for individuals with prior infection), our observation adds to the series of real-world data demonstrating the enhanced and more durable immune response evoked by booster vaccinations following prior infection.

Less Than 1-Year Quiescent Period After Septic Arthritis of the Hip is Associated With High Risk of Periprosthetic Joint Infection Following Total Hip Arthroplasty

BackgroundApproximately 20,000 patients are diagnosed with septic arthritis annually, with 15% specifically affecting the hip joint. These cases exacerbate arthritic changes, often warranting a total hip arthroplasty (THA). Given their prior history of infection, these patients are predisposed to subsequent periprosthetic joint infections (PJIs). Multiple studies suggest delaying THA after a native septic hip, but no study utilizing a large cohort examined the specific timing to mitigate post-THA PJI risk within a short (<1 year) quiescent period after septic arthritis. We sought to compare patients who were diagnosed with septic hip arthritis at time intervals (0-6, or 6-12 months) prior to an ipsilateral primary THA to a cohort of THA patients who never had a septic hip history. Specifically, we assessed: from 90 days to 2 years (1) revisions due to PJI and (2) associated risk factors for PJI at 2-years. MethodsA national, all-payer database was queried to identify all patients who underwent a primary THA between 2010 and 2021 and patients who had prior ipsilateral septic hip arthritis were characterized using International Classification of Disease and Current Practice Terminology codes (n = 1,052). A randomized sample of patients who never had a history of septic arthritis prior to undergoing THA was used as a nonseptic group comparison (n = 5,000). The incidences of PJI at 90 days through two years were then identified and compared using bivariate chi-square analyses. Risk factors for post-THA PJIs were then analyzed using multivariate regression models. ResultsThe septic arthritis cohorts were more likely to require revisions due to PJIs, as compared to the non-septic group at 90 days, 1 year, and 2 years (all P < .0001). Patients who were diagnosed with septic arthritis between 0 and 6 months prior to THA were at greater PJI risk at both one-year (odds ratio (OR) of 43.1 versus 29.6, P < .0001) and two years (OR of 38.3 versus 22.1, P < .0001) compared to patients who had diagnoses between 6 and 12 months. Diabetes mellitus, obesity, and tobacco use were associated risk factors for PJIs at 2 years in the septic hip cohort in comparison to the cohort without a septic hip history. ConclusionLess than a 1-year quiescent period after septic arthritis is associated with a 38 times increased risk and a 22 times risk for post-THA PJI, at 0 and 6 months and 6 and 12 months, respectively. Though patients who undergo THA greater than 6 months after their septic arthritis treatment have a decreased risk compared to those between 0 and 6 months the risks are still high. Orthopaedic surgeons should be aware of the increased risks of PJIs when considering performing a THA in patients with a history of septic arthritis.

Comparison Between Vancomycin and Gentamicin for Intraoperative Presoaking of Hamstring Graft in Primary Anterior Cruciate Ligament Reconstruction

IntroductionPostoperative infection is an uncommon complication with grave consequences following anterior cruciate ligament reconstruction (ACLR). Presoaking of the hamstring graft with antibiotics results in a lower rate of infection. The purpose of the current study was to compare the efficacy of two commonly used antibiotics, vancomycin and gentamicin, in reducing infection rates following anterior cruciate ligament reconstruction.MethodsThe retrospective study included a total of 578 patients who underwent arthroscopic anterior cruciate ligament reconstruction between June 2015 and October 2021. The timeline was categorized as the period between June 2015 to October 2018 (Vancomycin presoaking of hamstring graft) and November 2018 to October 2021 (Gentamicin presoaking of hamstring graft). All patients were examined for the development of infection, causative organism, and treatment received. Patients with intravenous drug abuse, alcoholism, steroid use, revision cases, and a prior history of infection in the knee were excluded from the study. Fisher’s exact test was used for comparison of categorical data, and Poisson regression analysis was carried out to calculate incidence rate ratios after adjusting for confounding variables.ResultsPresoaking of hamstring grafts with vancomycin was carried out in 224 patients, and gentamicin was used in 354 patients. In total, three patients in the vancomycin and four patients in the gentamicin groups developed an intraarticular infection, and the difference in infection rate between the two groups was not statistically significant (p=0.919). Coagulase-negative Staphylococcus aureus was isolated in four cases, Enterobacter cloacae in one, and no organism was seen in two cases. The groups were comparable in terms of age (p=0.563), smoking (p=0.84), sex (p=0.359), and operative time (p=0.09).ConclusionPresoaking of hamstring autografts with gentamicin intraoperatively is a good alternative to vancomycin in the prevention of infection following arthroscopic anterior cruciate ligament reconstruction.

Non-compliance to social distancing during COVID-19 pandemic: A comparative cross-sectional study between the developed and developing countries.

Background: Despite mass vaccination campaigns, the world has seen a steady rise in the number of SARS-CoV-2 cases, with 178,765,626 cases and 3,869,994 COVID-19 related deaths by June 19th, 2021. Therefore, it is important to enforce social distancing to control its spread. With the variation observed in the severity of the pandemic in different countries, it is also imperative to study the social distancing behaviors amongst the population in developed and developing countries.Design and methods: In this cross-sectional study, a total of 394 participants from 14 different countries were surveyed via an online REDCap form.Results: In this study, it was highlighted that despite adequate knowledge, the overall compliance to COVID-19 related preventive measures remains poor, the lowest being in the senior age group (≥ 65 years), and the highest being in adults aged between 25-64 years (p=0.003). Population from the developing countries were more compliant to all preventative measures against COVID-19 spread, except for handwashing, where the difference between the two populations remained insignificant (p=0.038, p<0.001, p=0.016) Socioeconomic status, prior history of COVID-19 infection or presence of comorbidities did not significantly affect compliance rates, however, participants with no prior history of this infection were found to be more compliant to donning a mask in public as compared to those with a positive history (p=0.044).Conclusions: Since compliance remains subpar in both the developing and the developed countries, mass campaigns about COVID-19 related preventive measures remain essential in controlling the disease spread. Significance for public health Through this research design, we hope to identify the socioeconomic and demographic factors, and their impact on people’s behaviours and attitudes towards adopting social distancing protocols to protect themselves and those around them from the SARS-CoV-2 virus. By understanding the population’s mindset and the factors that contribute to governing their behaviours, government policy makers can then employ short- and long-term strategies to address these components, and pass laws that have a higher probability of being accepted and followed by the masses. This study will further assess socioeconomic and cultural reasons that result in variations to compliance by comparing the difference in behaviours and attitudes adopted towards social distancing in both the developed and the developing countries.

Antibody response to the first dose of AZD1222 vaccine in COVID-19 convalescent and uninfected individuals in Bangladesh

Background Vaccination with the Oxford-AstraZeneca COVID-19 vaccine (AZD1222) initially started in the UK and quickly implemented around the Globe, including Bangladesh. Up to date, more than nine million doses administrated to the Bangladeshi public. Method Herein, we studied the antibody response to the first dose of AZD1222 in 86 Bangladeshi individuals using in-house ELISA kits. Study subjects were categorized into two groups, convalescent and uninfected, based on prior infection history and SARS-CoV-2 nucleocapsid-IgG profiles. Results All the convalescent individuals presented elevated spike-1-IgG compared to 90% of uninfected ones after the first dose. Day >28 post-vaccination, the convalescent group showed six times higher antibody titer than the uninfected ones. The most elevated antibody titers for the former and later group were found at Day 14 and Days >28 post-vaccination, respectively. The spike-1-IgA titer showed a similar pattern as spike-1-IgG, although in a low-titer. In contrast, the IgM titer did not show any significant change in either group. Conclusion High antibody titer in the convalescent group, signify the importance of the first dose among the uninfected group. This study advocates the integration of antibody tests in vaccination programs in the healthcare system for maximizing benefit.

1588P SARS-CoV-2 antibody seroprevalence and safety of vaccines in cancer patients who recovered from COVID-19

Background: Little is known about natural anti-SARS-CoV-2 antibody seroprevalence post COVID-19 and safety of vaccines in COVID-19 survivors with cancer. Methods: Among 2795 consecutive patients (pts) with COVID-19 and cancer registered to OnCovid between 01/2020 and 02/2021, we examined natural seroprevalence of anti-SARS-CoV-2 Antibodies (SC2Ab, IgM or IgG) in pts tested post-infection. We analysed prevalence and safety of SARS-Cov-2 vaccine administration in pts who underwent clinical re-assessment at participating institutions. Results: Out of 350 pts tested for SC2Ab, 318 (90.9%) had a positive SC2Ab titre post-convalescence. Neither baseline features (sex, age, comorbidities, smoking history, tumour stage/status, anticancer-therapy and primary tumour) nor COVID-19-specific features (complications, hospitalization, sequelae) were significantly associated SC2Ab status. Receipt of COVID-19 specific therapy was higher among SC2Ab+ pts (62.6% vs 40.6%, p=0.0156). Out of 593 pts with known vaccination status, 178 (30%) had received 1 dose, whilst 38 pts (6.4%) received 2 doses of mRNA based (70.2%) or viral vector vaccine (17.4%). Vaccinated pts were more likely aged ≥65 years (59% vs 48.3%, p=0.0172), with loco-regional tumour stage (56% vs 40.8%, p=0.0014), on anti-cancer therapy at COVID-19 (49.1% vs 38.2%, p=0.0168) and history of prior hospitalisation due to COVID-19 (61.8% vs 48.3%, p=0.0029). Vaccine-related adverse events were reported for 18/56 evaluable pts (32.1%) and included injection site reactions (50%), fever (44.4%), arthralgias (33.3%), fatigue (33.3%) and allergy (5.5%). No long-term vaccine-related morbidity was reported. Conclusions: We report high seroprevalence (>90%) of SC2Ab in convalescent cancer pts who survived COVID-19 irrespective of baseline demographics, oncological characteristics and COVID-19 severity. COVID-19 vaccines appear to be safe in cancer pts with history of prior infection. Clinical trial identification: NCT04393974. Legal entity responsible for the study: Imperial College London. Funding: Has not received any funding. Disclosure: D.J. Pinato: Financial Interests, Personal, Invited Speaker: ViiV Healthcare;Financial Interests, Personal, Invited Speaker: Bayer;Financial Interests, Personal, Advisory Board: Eisai;Financial Interests, Personal, Advisory Board: Amgen;Financial Interests, Personal, Advisory Board: BMS;Financial Interests, Personal, Advisory Board: Pfizer;Financial Interests, Personal, Advisory Board: Nanostring tech. A. Cortellini: Financial Interests, Personal, Advisory Board: MSD;Financial Interests, Personal, Advisory Board: BMS;Financial Interests, Personal, Advisory Board: Roche;Financial Interests, Personal, Invited Speaker: Novartis;Financial Interests, Personal, Advisory Board: SunPharma;Financial Interests, Personal, Invited Speaker: AstraZeneca;Financial Interests, Personal, Invited Speaker: Astellas. All other authors have declared no conflicts of interest.

Humoral immune responses during SARS-CoV-2 mRNA vaccine administration in seropositive and seronegative individuals

BackgroundThe global pandemic of coronavirus disease 2019 (COVID-19) is caused by infection with the SARS-CoV-2 virus. Currently, there are three approved vaccines against SARS-CoV-2 in the USA, including two based on messenger RNA (mRNA) technology that has demonstrated high vaccine efficacy. We sought to characterize humoral immune responses, at high resolution, during immunization with the BNT162b2 (Pfizer-BioNTech) vaccine in individuals with or without prior history of natural SARS-CoV-2 infection.MethodsWe determined antibody responses after each dose of the BNT162b2 SARS-CoV-2 vaccine in individuals who had no prior history of SARS-CoV-2 infection (seronegative) and individuals that had previous viral infection 30–60 days prior to first vaccination (seropositive). To do this, we used both an antibody isotype-specific multiplexed bead-based binding assays targeting multiple SARS-CoV-2 viral protein antigens and an assay that identified potential SARS-CoV-2 neutralizing antibody levels. Moreover, we mapped antibody epitope specificity after immunization using SARS-CoV-2 spike protein peptide arrays.ResultsAntibody levels were significantly higher after a single dose in seropositive individuals compared to seronegative individuals and were comparable to levels observed in seronegative individuals after two doses. While IgG was boosted by vaccination for both seronegative and seropositive individuals, only seronegative individuals had increased IgA or IgM antibody titers after primary immunization. We identified immunodominant peptides targeted on both SARS-CoV-2 spike S1 and S2 subunits after vaccination.ConclusionThese findings demonstrated the antibody responses to SARS-CoV-2 immunization in seropositive and seronegative individuals and provide support for the concept of using prior infection history as a guide for the consideration of future vaccination regimens. Moreover, we identified key epitopes on the SARS-CoV-2 spike protein that are targeted by antibodies after vaccination that could guide future vaccine and immune correlate development.

Effectiveness of influenza vaccination in infants and toddlers with and without prior infection history: The Japan Environment and Children’s Study

We calculated the Poisson-regression-adjusted relative risk (RR) of new influenza infection by vaccination, prior infection, and vaccination after prior infection in a large Japanese birth cohort, using data from ≤89,253 children aged 6 months to 3 years. The effectiveness of risk reduction (1 − RR) by vaccination at ages 1.5–3 years was 21%–31%. The RR of new infection after prior infection vs. no prior infection was 2.58–19.3 at age 1–3 years. An analysis of the 1 − RR data stratified by having at least one senior sibling and/or attending nursery school revealed that vaccination reduced the RR by 22%–40%. The 1 − RR of new infection was 21% in 3-year-old children who were vaccinated after prior infection. All these findings are statistically significant. The results consistently indicate that, regardless of having at least one senior sibling, attending nursery school, and/or being previously infected with influenza, infants and toddlers will benefit from influenza vaccination.