Need For Booster Vaccination Research Articles

VIVALDI Cohort Profile: Using linked, routinely collected data and longitudinal blood sampling to characterise COVID-19 infections, vaccinations, and related outcomes in care home staff and residents in England.

VIVALDI (ISRCTN14447421) is a government-funded longitudinal open observational cohort study of staff and residents in care homes for older people in England. The study aimed to describe epidemiology (including seroprevalence) and immune responses to COVID-19 in a subset of care homes, in the context of extremely high mortality in this setting, in the first 12-18 months of the pandemic. Data linkage to routine health data was undertaken for all staff and residents and a subset of individuals who consented to sequential blood sampling to investigate SARS-CoV-2 immunity. This paper aims to describe the samples stored within the VIVALDI biobank and associated linked data, available for use by researchers. Over 70,000 individuals from 346 care homes were included in the data linkage cohort (1 st March 2020-31 st March 2023). 4971 samples from 2264 individuals (1415 staff, 827 residents) collected between 29 th October 2020 and 10 th March 2023 are stored. Amongst these samples, there was a maximum of seven per participant however, 217 (26.2%) residents and 551 (38.9%) staff participated in one round only. Key study findings include high COVID-19 seroprevalence among surviving residents, exceeding rates in community-dwelling peers. COVID-19 vaccinations generated robust immune responses in staff and residents which waned, supporting the need for booster vaccination, particularly in response to new variants. Prior infection significantly improved vaccine-induced immune responses, however protection from infection declined following Omicron variant emergence. This is a unique cohort of pre- and post-infection samples linked to data on COVID-19 infections, vaccinations, and outcomes. The cohort spans host immune response evolution to infection and vaccination in this rarely sampled population of frail older care home residents who are especially vulnerable to infection and severe outcomes. These samples can be used to investigate biological mechanisms behind disparate infection responses in older people and make a valuable contribution to research into ageing.

Booster Vaccination with BNT162b2 Improves Cellular and Humoral Immune Response in the Pediatric Population Immunized with CoronaVac.

The SARS-CoV-2 Omicron variant and its sublineages continue to cause COVID-19-associated pediatric hospitalizations, severe disease, and death globally. BNT162b2 and CoronaVac are the main vaccines used in Chile. Much less is known about the Wuhan-Hu-1 strain-based vaccines in the pediatric population compared to adults. Given the worldwide need for booster vaccinations to stimulate the immune response against new Omicron variants of SARS-CoV-2, we characterized the humoral and cellular immune response against Omicron variant BA.1 in a pediatric cohort aged 10 to 16 years who received heterologous vaccination based on two doses of CoronaVac, two doses of CoronaVac (2x) plus one booster dose of BNT162b2 [CoronaVac(2x) + BNT162b2 (1x)], two doses of CoronaVac plus two booster doses of BNT162b2 [CoronaVac(2x) + BNT162b2 (2x)], and three doses of BNT162b2. We observed that the [CoronaVac(2x) + BNT162b2 (2x)] vaccination showed higher anti-S1 and neutralizing antibody titers and CD4 and CD8 T cell immunity specific to the Omicron variant compared to immunization with two doses of CoronaVac alone. Furthermore, from all groups tested, immunity against Omicron was highest in individuals who received three doses of BNT162b2. We conclude that booster vaccination with BNT162b2, compared to two doses of CoronaVac alone, induces a greater protective immunity.

Shift in SARS-CoV-2 variants of concern from Delta to Omicron was associated with reduced hospitalizations, increased risk of breakthrough infections but lesser disease severity

BackgroundCOVID-19 epidemiology changed with the emergence of SARS-CoV-2 variants of concern (VOC). Pakistan administered mostly inactivated vaccines. We investigated the association between VOC and breakthrough infections in a mixed-vaccination-status population of Karachi. MethodsWe investigated SARS-CoV-2 VOC tested in 392 respiratory specimens collected between May and December 2021. Data for age, sex, hospital admission, vaccinations, together with CT values of the diagnostic PCR test were analyzed. ResultsThe median age of COVID-19 cases tested was 40 (27−57) years and 43.4% were female. Delta variants were most common (56.4%) followed by Alpha (15.9%), Omicron (12.2%), Beta/Gamma (11.3%), and others (4.3%). Eighteen percent of cases were hospitalized whereby, predominant VOC were Beta/Gamma (40.8%), Alpha (35.2%) and Delta (22.5%). Overall, 55.4% of individuals were fully vaccinated, 7.4% were partially vaccinated and 37.2% were unvaccinated. Most (74.6%) inpatients were unvaccinated. Vaccines comprised inactivated (85.34%), single-shot vector (8.62%), two-shot vector (3.02%) and mRNA (3.02%) types. Omicron variants showed lower viral loads as compared to Alpha, Beta/Gamma, and Delta (p = 0.017). The risk of infection with Delta and Omicron variants was higher, 8 weeks after vaccination. The majority of those with breakthrough infections after receiving inactivated vaccines acquired COVID-19 within 4 months of vaccination. ConclusionOur data highlights the shifting of VOC from Delta to Omicron during 2021 and that COVID-19 vaccinations reduced both hospitalizations and viral transmission. It informs on the increased risk of breakthrough infection within 8 weeks of vaccination, indicating the need for booster vaccinations.

Response to COVID-19 vaccination in patients on cancer therapy: Analysis in a SARS-CoV-2-naïve population.

Cancer patients have increased morbidity and mortality from COVID-19, but may respond poorly to vaccination. The Evaluation of COVID-19 Vaccination Efficacy and Rare Events in Solid Tumors (EVEREST) study, comparing seropositivity between cancer patients and healthy controls in a low SARS-CoV-2 community-transmission setting, allows determination of vaccine response with minimal interference from infection. Solid tumor patients from The Canberra Hospital, Canberra, Australia, and healthy controls who received COVID-19 vaccination between March 2021 and January 2022 were included. Blood samples were collected at baseline, pre-second vaccine dose and at 1, 3 (primary endpoint), and 6months post-second dose. SARS-CoV-2 anti-spike-RBD (S-RBD) and anti-nucleocapsid IgG antibodies were measured. Ninety-six solid tumor patients and 20 healthy controls were enrolled, with median age 62years, and 60% were female. Participants received either AZD1222 (65%) or BNT162b2 (35%) COVID-19 vaccines. Seropositivity 3months post vaccination was 87% (76/87) in patients and 100% (20/20) in controls (p=.12). Seropositivity was observed in 84% of patients on chemotherapy, 80% on immunotherapy, and 96% on targeted therapy (differences not satistically significant). Seropositivity in cancer patients increased from 40% (6/15) after first dose, to 95% (35/37) 1month after second dose, then dropped to 87% (76/87) 3months after second dose. Most patients and all controls became seropositive after two vaccine doses. Antibody concentrations and seropositivity showed a decrease between 1 and 3months post vaccination, highlighting need for booster vaccinations. SARS-CoV-2 infection amplifies S-RBD antibody responses; however, cannot be adequately identified using nucleocapsid serology. This underlines the value of our COVID-naïve population in studying vaccine immunogenicity.

VIVALDI Cohort Profile: Using linked, routinely collected data and longitudinal blood sampling to characterise COVID-19 infections, vaccinations, and related outcomes in care home staff and residents in England

VIVALDI (ISRCTN14447421) is a government-funded longitudinal open observational cohort study of staff and residents in care homes for older people in England. The study aimed to describe epidemiology (including seroprevalence) and immune responses to COVID-19 in a subset of care homes, in the context of extremely high mortality in this setting, in the first 12-18 months of the pandemic. Data linkage to routine health data was undertaken for all staff and residents and a subset of individuals who consented to sequential blood sampling to investigate SARS-CoV-2 immunity. This paper aims to describe the samples stored within the study biobank, available for use by researchers. Over 70,000 individuals from 346 care homes were included in the data linkage cohort (1st March 2020–31st March 2023). 4975 samples from 2268 individuals (1419 staff, 827 residents) collected between 29th October 2020 and 10th March 2023 are stored. Amongst these samples, there was a maximum of seven per participant however, 217 (26.2%) residents and 555 (39.1%) staff participated in one round only. Key study findings include high COVID-19 seroprevalence among surviving residents, exceeding rates in community-dwelling peers. COVID-19 vaccinations generated robust immune responses in staff and residents which waned, supporting the need for booster vaccination, particularly in response to new variants. Prior infection significantly improved vaccine-induced immune responses, however protection from infection declined following Omicron variant emergence. This is a unique cohort of pre- and post-infection samples linked to data on COVID-19 infections, vaccinations, and outcomes. The cohort spans host immune response evolution to infection and vaccination in this rarely sampled population of frail older care home residents who are especially vulnerable to infection and severe outcomes. These samples can be used to investigate biological mechanisms behind disparate infection responses in older people and make a valuable contribution to research into ageing.

The humoral and cellular immune responses following booster vaccination with SARS-CoV-2 mRNA in people living with human immunodeficiency virus

IntroductionPeople living with human immunodeficiency virus (PLWH) have higher mortality rates from COVID-19 than those without HIV. Additionally, the seroconversion rate of antibodies following a second dose of SARS-CoV-2 vaccine is lower in PLWH than non-infected individuals, indicating the need for booster vaccination. Here, we evaluated the humoral and cellular immune responses to booster SARS-CoV-2 vaccination in PLWH. MethodsThe dynamics of anti-spike IgG titers and antigen-specific interferon (IFN)-γ levels to SARS-CoV-2 vaccination were assessed over a 6-month period following a third vaccination of 34 PLWH. ResultsAntibody titers for humoral immunity were 50 % lower at 24 weeks post-vaccination than those at 12 weeks. However, those at 24 weeks after the booster vaccination were approximately eight times higher than before. Regarding cellular immunity, IFN-γ levels at 24 weeks after the third vaccination were lower than those at 12 weeks, but nearly 90 % of participants maintained a cut-off value of ≥0.15 IU/mL. A comparison between two groups with CD4+ T lymphocytes counts of <500/μL or ≥500/μL exhibited no statistically significant differences in antibody or IFN-γ levels. However, in the group with CD4+ T lymphocyte counts of <500/μL, the rate of IFN-γ above the cut-off value at 24 weeks after the booster vaccination was lower than that of ≥500/μL. ConclusionAn immune response is expected in PLWH given successful antiretroviral therapy with booster SARS-CoV-2 vaccination. However, caution should be exercised for cases with low CD4+ T-lymphocyte counts. (240/250 words)

The persistence of SARS-CoV-2 neutralizing antibodies after COVID-19: A one-year observation. Is a SARS-CoV-2 vaccination booster dose necessary?

The aim of this study was to investigate the persistence of SARS-CoV-2 neutralizing antibodies (NAbs) one year after contracting COVID-19. The study included 38 patients - 34 men and 4 women - suffering from COVID-19 between March 15 and May 26, 2020. The median age in the group was 31 years, ranging from 22 to 67 years. The levels of neutralizing antibodies were measured at three time-points - baseline, 6 months, and 12 months. The primary endpoint was a post-infection positive result for NAbs (> 15 AU/ml; Liaison SARS-CoV-2 S1/S2 IgG quantitative test) 12 months after infection. The median level of NAbs after 12 months was 26.5 AU/ml. At the end of observation (12 months), 21 of the 38 patients had a NAb level of >15 AU/ml (positive). The median antibody half-life was 5.8 months. A high percentage of the patients maintained positive levels of antibodies 6 and 12 months after COVID-19 infection. The dynamics of the antibody level decline suggests the need for booster vaccination at least once a year.

Humoral SARS-CoV-2 immunogenicity wanes 3 months after heterologous inactivated vaccine followed by ChAdOx1 nCoV-19 in autoimmune rheumatic diseases.

Alongside vaccine hesitancy, impaired and waning immunity in autoimmune rheumatic diseases (ARDs) are barriers to immunization. The timeframe of immunity waning in ARD remains unclear. We aimed to examine the waning of humoral immunogenicity in a cohort of ARD patients who received the heterologous inactivated vaccine followed by the adenoviral vector SAR-CoV-2 vaccine at a 3-month follow-up. The levels of SARS-CoV-2 anti-RBD IgG were evaluated at 1 and 3 months in adults with ARDs (n = 29) and age- and sex-matched healthy controls (HC) that received the heterologous prime-boost CoronaVac vaccine followed by the ChAdOx1 nCoV-19 vaccine. Seropositivity was defined as anti-receptor binding domain (RBD) IgG levels of ≥ 7.15 binding antibody units (BAU)/mL. The kinetic properties of the vaccines were evaluated based on the ratio of anti-RBD IgG values obtained at each follow-up. Disease activity was evaluated. The seropositivity rate was lower among patients with ARDs than among HCs (89.7% vs. 100%, p = 0.237). At 3 months, the median (IQR) anti-RBD IgG level was lower among patients with ARDs than among HCs (122.3 [30.6, 247.8] vs. 294.2 [127.4,605.7] BAU/mL, p = 0.006). Mean antibody levels in patients with ARDs decreased 3.5 (1.9)-fold within 3 months post-vaccination (122.3 [30.6, 247.8] vs. 279.9 [86,1076.5] BAU/mL, p < 0.001). Disease flare-ups occurred in three patients. Our findings included changes to anti-RBD IgG levels and may inform vaccination strategies. SAR-CoV2 vaccine-induced immunity was lower in patients with ARDs than in HCs and decreased within 3 months, suggesting a need for booster vaccinations.

Coverage rates for diphtheria, tetanus, poliomyelitis, and pertussis age-specific booster recommendations in France: 2018 update of the real-world cohort analysis

The French National Immunization Program was updated in 2013 for vaccination against diphtheria, tetanus, pertussis, and poliomyelitis. Our previous findings on the evolution of age-specific booster vaccination coverage rates (VCRs) up to 2017 suggested suboptimal vaccination coverages due to the pre-2013 recommendation-residual vaccination practices. In the current analysis, we evaluated all age-specific booster VCR and distribution of age at vaccination visits in 2018. In this retrospective observational cohort study, the cumulative booster VCRs were updated at all vaccination visits up to 2018 among the people who were eligible for a booster vaccination, using a 1/97th random sample of French national healthcare reimbursement databases. The cumulative booster VCR for individuals from all age groups increased from 2017 to 2018, except for 85-years-old vaccination visit. Majority of the individuals from all age groups were vaccinated (boosted) with a vaccine containing the pertussis valence. In 2018, sharp peaks corresponding to the recommended ages for booster vaccination visits were observed for individuals aged 6, 11 to 13, 25, 45, and 65 years. Our study reiterates suboptimal coverages in France and implies the need for booster vaccination throughout life for the protection of the population.

Neutralizing Antibodies against the SARS-CoV-2 Delta and Omicron BA.1 following Homologous CoronaVac Booster Vaccination.

Emerging severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) variants have reduced susceptibility to neutralization by vaccines. In response to the constantly updated variants, a global vaccine booster vaccination program has been launched. In this study, we detected neutralizing antibody levels against wild-type (WT), Delta (B1.617.2), and Omicron BA.1 viruses in serum after each dose of CoronaVac vaccination. We found that booster vaccination significantly increased the levels of neutralizing antibodies against WT, Delta, and Omicron BA.1. Compared with only one vaccination, neutralizing antibody levels increased by 19.2-21.6-fold after a booster vaccination, whilst two vaccinations only produced a 1.5-3.4-fold increase. Our results support the conclusion that the CoronaVac vaccine booster can increase neutralizing antibody levels and cross-reactivity and enhance the body's ability to effectively resist the infection of new coronavirus variants, emphasizing the need for booster vaccination.

Efficient recall of SARS-CoV-2 variant-reactive B cells and T responses in the elderly upon heterologous mRNA vaccines as boosters.

Waning antibody levels against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and the emergence of variants of concernhighlight the need for booster vaccinations. This is particularly important for the elderly population, who are at a higher risk of developing severe coronavirus disease 2019 (COVID-19) disease. While studies have shown increased antibody responses following booster vaccination, understanding the changes in T and B cell compartments induced by a third vaccine dose remains limited. We analyzed the humoral and cellular responses in subjects who received either a homologous messenger RNA(mRNA) booster vaccine (BNT162b2 + BNT162b2 + BNT162b2; ''BBB") or a heterologous mRNA booster vaccine (BNT162b2 + BNT162b2 + mRNA-1273; ''BBM") at Day 0 (prebooster), Day 7, and Day 28 (postbooster). Compared withBBB, elderly individuals (≥60 years old) who received the BBM vaccination regimen display higher levels of neutralizing antibodies against the Wuhan and Delta strains along with a higher boost in immunoglobulin G memory B cells, particularly against the Omicron variant. Circulating T helper type 1(Th1), Th2, Th17, and T follicular helper responseswere also increased in elderly individuals given the BBM regimen. While mRNA vaccines increase antibody, T cell, and B cell responses against SARS-CoV-2 1 month after receiving the third dose booster, the efficacy of the booster vaccine strategies may vary depending on age group and regimen combination.

COVID-19-Impfstrategien für Beschäftigte deutscher Kliniken: Ergebnisse einer Befragung von Leitungen der (Krankenhaus‑)Hygiene im Rahmen des B-FAST-Projektes

ZusammenfassungHintergrund und ZielZu Beginn der COVID-19-Impfkampagne in Deutschland wurden Beschäftigte in medizinischen Einrichtungen aufgrund des hohen Expositionsrisikos und des Kontakts mit vulnerablen Gruppen priorisiert gegen SARS-CoV‑2 geimpft. Die Krankenhäuser waren angehalten die Impfungen ihrer Beschäftigten möglichst schnell zu organisieren und durchzuführen. Ziel der vorliegenden Arbeit war es, die Impfstrategie für die Mitarbeitenden deutscher Kliniken zu erfassen.MethodenIn einer Querschnittstudie mit selbstentwickeltem Fragebogen wurden die Leitungen der (Krankenhaus‑)Hygiene aller deutschen Universitätskliniken sowie der Nicht-Universitätskliniken in Niedersachsen und Bayern im März 2021 befragt. Die Daten wurden nach den beiden Versorgungsstufen stratifiziert.Ergebnisse100 von 416 versendeten Fragebögen wurden vollständig ausgefüllt (Universitätsklinik: 33, Nicht-Universitätsklinik: 67). Universitätskliniken berichteten von einer größeren Impfkapazität als Nicht-Universitätskliniken, ein begrenzender Faktor waren die ungewissen Impfstofflieferungen. 89 % der Kliniken planten Informationskampagnen zum Thema Impfung oder hatten diese bereits durchgeführt. 70 % gaben an, keine Antikörpertests bei geimpften Beschäftigten durchführen zu wollen. Eine Nachverfolgung geimpfter Beschäftigter zur Detektion möglicher SARS-CoV-2-Infektionen mittels Erregernachweis durch PCR wurde von 41 % geplant. Im Falle des Nachweises einer SARS-CoV-2-Infektion bei geimpften Beschäftigten hatten 72 % weitere Diagnostik geplant.DiskussionAlle Krankenhäuser konnten eine schnelle Umsetzung der COVID-19-Vakzinierung ihrer Beschäftigten erreichen. Zum Zeitpunkt der Befragung gab es große Unsicherheit bezüglich des Umgangs mit Durchbruchsinfektionen und der Notwendigkeit von Auffrischimpfungen.

Humoral and cellular immune response over 9 months of mRNA-1273, BNT162b2 and ChAdOx1 vaccination in a University Hospital in Spain

Scarce data have been reported about cellular immunity and longevity for different COVID-19 vaccination schedules. We carried out a prospective study enrolling 709 healthcare workers receiving two doses of mRNA-1273, BNT162b2, ChAdOx1, ChAdOx1/BNT162b2 or ChAdOx1 single dose to compare humoral and cellular immunogenicity across 9 months. Higher SARS-CoV-2 spike antibody levels were observed among individuals with hybrid immunity with one dose of any vaccine in comparison to uninfected individuals receiving two doses (mRNA-1273: 20,145 vs 4295 U/mL; BNT162b2: 15,659 vs 1959 U/mL; ChAdOx1: 5344 vs 2230 U/mL), except for ChAdOx1/BNT162b2 heterologous schedule (12,380 U/mL). Naturally infected individuals did not increase substantially the titers after the second dose and showed higher levels throughout the 9 months follow-up. The mean elimination half-life of antibodies among COVID-19 naïve participants was 98, 111, 60 and 36 days, for mRNA-1273, BNT162b2, ChAdOx1/ChAdOx1 and ChAdOx1/BNT162b2, respectively. Cellular immunity was preserved in 96%, 98%, 88% and 92% of uninfected individuals who received mRNA-1273, BNT162b2, ChAdOx1/ChAdOx1 and ChAdOx1/BNT162b2 after 6/9 months. Individuals with specific T cells showed robust long lasting protection, especially when m-RNA based vaccines are inoculated. These data may influence the validity of the vaccination passport and the need for booster vaccinations.

Antibody profile in post-vaccinated & SARS-CoV-2 infected individuals.

During the COVID-19 pandemic it was important to assess the antibody profile in individuals vaccinated with Covaxin (BBV152) and Covishield (ChAdOx1 nCoV-19) with both 28 and 84 days gaps between two doses, those infected with SARS-CoV-2 and post-COVID-19-infected individuals vaccinated with only one dose of either of the vaccines. The present study was aimed to assess these objectives. Fifty real time reverse transcription-polymerase chain reaction (qRT-PCR)-confirmed COVID-19-infected individuals, along with 90 COVID-19-naïve (BBV152 and ChAdOx1 nCov-19)-vaccinated individuals, were included in the study. Individuals who received a single dose of either vaccine with a confirmed past diagnosis of SARS-CoV-2 infection (n=15) were also included. Blood samples were collected strictly between the 4th and 5th wk after development of symptoms for SARS-CoV-2 infected individuals and after the first/second vaccination dose. Antibody profile assessment was done using whole-virus, spike-receptor binding domain (RBD) and nucleocapsid-specific ELISA kits along with neutralizing antibody kit. There was an overall 97.7 per cent seropositivity rate in vaccinated individuals, and a strong correlation (R2=0.8, P<0.001) between neutralizing and spike-RBD antibodies. Among individuals who received two standard doses of ChAdOx1 nCoV-19 vaccine, the spike antibody levels developed were of higher titre with a longer prime boost interval than in those with shorter intervals (P<0.01). Individuals vaccinated with two doses as well as only one dose post-SARS-CoV-2 infection had high neutralizing and spike-specific antibodies. High neutralizing and spike-specific antibodies were developed in individuals vaccinated only with one dose of either vaccine post-SARS-CoV-2 infection. With the main priority being vaccinating majority of the population in our country, single-dose administration to such individuals would be a sensible way to make the most of the limited supplies. Furthermore, neutralizing antibody levels observed in COVID-19-naïve vaccinees imply the need for booster vaccination.

Rapid Evaluation of Vaccine Booster Effectiveness against SARS-CoV-2 Variants.

ABSTRACTAs the COVID-19 pandemic continues, countries around the world are switching toward vaccinations and boosters to combat the pandemic. However, waning immunity against SARS-CoV-2 wild-type (WT) and variants have been widely reported. Booster vaccinations have shown to be able to increase immunological protection against new variants; however, the protection observed appears to decrease quickly over time suggesting a second booster shot may be appropriate. Moreover, heterogeneity and waning of the immune response at the individual level was observed suggesting a more personalized vaccination approach should be considered. To evaluate such a personalized strategy, it is important to have the ability to rapidly evaluate the level of neutralizing antibody (nAbs) response against variants at the individual level and ideally at a point of care setting. Here, we applied the recently developed cellulose pulled-down virus neutralization test (cpVNT) to rapidly assess individual nAb levels to WT and variants of concerns in response to booster vaccination. Our findings confirmed significant heterogeneity of nAb responses against a panel of SARS-CoV-2 variants, and indicated a strong increase in nAb response against variants of concern (VOCs) upon booster vaccination. For instance, the nAb response against current predominant omicron variant was observed with medians of 88.1% (n = 6, 95% CI = 73.2% to 96.2%) within 1-month postbooster and 70.7% (n = 22, 95% CI = 66.4% to 81.8%) 3 months postbooster. Our data show a point of care (POC) test focusing on nAb response levels against VOCs can guide decisions on the potential need for booster vaccinations at individual level. Importantly, it also suggests the current booster vaccines only give a transient protective response against some VOC and new more targeted formulations of a booster vaccine against specific VOC may need to be developed in the future.IMPORTANCE Vaccination against SARS-CoV-2 induces protection through production of neutralization antibodies (nAb). The level of nAb is a major indicator of immunity against SARS-CoV-2 infection. We developed a rapid point-of-care test that can monitor the nAb level from a drop of finger stick blood. Here, we have implemented the test to monitor individual nAb level against wild-type and variants of SARS-CoV-2 at various time points of vaccination, including post-second-dose vaccination and postbooster vaccination. Huge diversity of nAb levels were observed among individuals as well as increment in nAb levels especially against Omicron variant after booster vaccination. This study evaluated the performance of this point-of-care test for personalized nAb response tracking. It verifies the potential of using a rapid nAb test to guide future vaccination regimens at both the individual and population level.

Antibody affinity and cross-variant neutralization of SARS-CoV-2 Omicron BA.1, BA.2 and BA.3 following third mRNA vaccination

There is limited knowledge on durability of neutralization capacity and antibody affinity maturation generated following two versus three doses of SARS-CoV-2 mRNA vaccines in naïve versus convalescent individuals (hybrid immunity) against the highly transmissible Omicron BA.1, BA.2 and BA.3 subvariants. Virus neutralization titers against the vaccine-homologous strain (WA1) and Omicron sublineages are measured in a pseudovirus neutralization assay (PsVNA). In addition, antibody binding and antibody affinity against spike proteins from WA1, BA.1, and BA.2 is determined using surface plasmon resonance (SPR). The convalescent individuals who after SARS-CoV-2 infection got vaccinated develop hybrid immunity that shows broader neutralization activity and cross-reactive antibody affinity maturation against the Omicron BA.1 and BA.2 after either second or third vaccination compared with naïve individuals. Neutralization activity correlates with antibody affinity against Omicron subvariants BA.1 and BA.2 spikes. Importantly, at four months post-third vaccination the neutralization activity and antibody affinity against the Omicron subvariants is maintained and trended higher for the individuals with hybrid immunity compared with naïve adults. These findings about hybrid immunity resulting in superior immune kinetics, breadth, and durable high affinity antibodies support the need for booster vaccinations to provide effective protection from emerging SARS-CoV-2 variants like the rapidly spreading Omicron subvariants.

Determining the Prevalence and Correlates of COVID-19 Booster Vaccine Hesitancy in the Singapore Population Following the Completion of the Primary Vaccination Series

In response to declining vaccine-induced immunity and the emergence of new COVID-19 variants, COVID-19 booster vaccination programmes have been widely launched in several high-income countries. However, public response has been slow, and scepticism about these programmes is rising in these settings. This study sought to identify the sociodemographic, emotional, and psychological factors associated with COVID-19 booster vaccine hesitancy in Singapore. Derived from a community cohort, 1005 fully vaccinated adults (62.1% female, mean age = 42.6 years) that had not received their COVID-19 booster shots completed an online survey between October and November 2021 on vaccination beliefs, intentions, and behaviours. Results indicated that despite completing the primary COVID-19 vaccination, 30.5% of those surveyed were hesitant about receiving the booster shot (25.9% unsure; 4.7% refused the booster), and 39.2% perceived more vaccine risks than benefits. Multivariable models indicated that a tertiary education, lower COVID-19 threat perception, lower perceived benefits, higher perceived concerns, a decreased need for booster vaccination, and a lower benefit/concerns differential score were associated with higher odds of booster vaccine hesitancy. Success in the primary vaccination series may not warrant widespread public acceptance for recurrent COVID-19 vaccination doses. In addressing booster vaccine hesitancy as restrictive measures and mandates are lifted, health perceptions relevant or unique to booster vaccine uptake should be considered.

Repeated information of benefits reduces COVID-19 vaccination hesitancy: Experimental evidence from Germany.

Many countries, such as Germany, struggle to vaccinate enough people against COVID-19 despite the availability of safe and efficient vaccines. With new variants emerging and the need for booster vaccinations, overcoming vaccination hesitancy gains importance. The research to date has revealed some promising, albeit contentious, interventions to increase vaccination intention. However, these have yet to be tested for their effectiveness in increasing vaccination rates. We conducted a preregistered survey experiment with N = 1,324 participants in Germany in May/June 2021. This was followed by a series of emails reminding participants to get vaccinated in August and concluded with a follow-up survey in September. We experimentally assess whether debunking vaccination myths, highlighting the benefits of being vaccinated, or sending vaccination reminders decreases hesitancy. In the survey experiment, we find no increase in the intention to vaccinate regardless of the information provided. However, communicating vaccination benefits over several weeks reduced the likelihood of not being vaccinated by 9 percentage points, which translates into a 27% reduction compared to the control group. Debunking vaccination myths and reminders alone also decreased the likelihood, yet not significantly. Our findings suggest that if soft governmental interventions such as information campaigns are employed, highlighting benefits should be given preference over debunking vaccination myths. Furthermore, it seems that repeated messages affect vaccination action while one-time messages might be insufficient, even for increasing vaccination intentions. Our study highlights the importance of testing interventions outside of survey experiments that are limited to measuring vaccination intentions-not actions-and immediate changes in attitudes and intentions-not long-term changes.

SARS-CoV-2 vaccine effectiveness against infection, symptomatic and severe COVID-19: a systematic review and meta-analysis

BackgroundThe temporal evolution of SARS-CoV-2 vaccine efficacy and effectiveness (VE) against infection, symptomatic, and severe COVID-19 is incompletely defined. The temporal evolution of VE could be dependent on age, vaccine types, variants of the virus, and geographic region. We aimed to conduct a systematic review and meta-analysis of the duration of VE against SARS-CoV-2 infection, symptomatic COVID-19 and severe COVID-19.MethodsMEDLINE, Scopus, Cochrane Central Register of Controlled Trials, Cochrane Database of Systematic Reviews, the World Health Organization Global Literature on Coronavirus Disease, and CoronaCentral databases were searched and studies were selected. Independent reviewers selected randomized controlled trials and cohort studies with the outcome of interest. Independent reviewers extracted data, and assessed the risk of bias. Meta-analysis was performed with the DerSimonian-Laird random-effects model with Hartung-Knapp-Sidik-Jonkman variance correction. The GRADE (Grading of Recommendations, Assessment, Development and Evaluation) approach was used to assess certainty (quality) of the evidence. Primary outcomes included VE as a function of time against SARS-CoV-2 infection, symptomatic and severe COVID-19.ResultsEighteen studies were included representing nearly 7 million individuals. VE against all SARS-CoV-2 infections declined from 83% in the first month after completion of the original vaccination series to 22% at 5 months or longer. Similarly, VE against symptomatic COVID-19 declined from 94% in the first month after vaccination to 64% by the fourth month. VE against severe COVID-19 for all ages was high overall, with the level being 90% (95% CI, 87–92%) at five months or longer after being fully vaccinated. VE against severe COVID-19 was lower in individuals ≥ 65 years and those who received Ad26.COV2.S.ConclusionsVE against SARS-CoV-2 infection and symptomatic COVID-19 waned over time but protection remained high against severe COVID-19. These data can be used to inform public health decisions around the need for booster vaccination.

MO914: Development of Antibody Response to SARS-COV-2 Vaccines in Haemodialysis Patients

Abstract BACKGROUND AND AIMS Previous data has shown a reduced immune response shortly after SARS-CoV-2 vaccinations in haemodialysis patients. We therefore investigated the long-term antibody response in patients from different outpatient dialysis centres at 4 weeks and 6 months after a complete vaccination against COVID-19. The results were compared with the humoral responses of non-dialysis subjects. METHODS We designed a retrospective multicentric cohort study, enrolling 106 haemodialysis patients and 50 non-dialysis patients after the SARS-CoV-2 vaccination. SARS-CoV-2 antibody testing was performed as part of routine clinical practice 4 weeks as well as 6 months after the immunization with chemiluminescence immunoassays designed to detect antibodies against the SARS-CoV-2 spike protein (Elecsys Anti-SARS-CoV-2 S, Roche Diagnostics, Mannheim, Germany). Testing was performed in the Institute of Laboratory Medicine of the University Hospital Munich. According to the manufacturer's specifications, anti-SARS-CoV-2 S titres &amp;gt;0.8 U/mL are considered reactive (sensitivity 98.8% and specificity 99.9%). Anti-SARS-CoV-2 S titres &amp;lt; 100 U/mL were defined as a low antibody response. RESULTS A total of 106 haemodialysis patients with a median age of 73 years received a SARS-CoV-2 vaccination (n = 105 mRNA, n = 1 AstraZeneca). Of these, 50 non-dialysis patients with a median age of 56 years received a SARS-CoV-2 vaccination (n = 45 mRNA, n = 5 mRNA/AstraZeneca). During the observational period, 8 haemodialysis patients and 2 non-dialysis patients additionally contracted a SARS-CoV-2 infection. Between the two testings, an overall decrease in anti-SARS-CoV-2 S antibody titres was observed (haemodialysis patients from a median of 252 to 95 U/mL, non-dialysis patients from a median of 1621 to 441 U/mL). At 6 months after the complete vaccination, 99 (93%) haemodialysis patients still presented with a detectable anti-SARS-CoV-2 spike antibody response (&amp;gt;0.8 U/mL), comparable to 100% of the non-dialysis subjects. However, 60 (57%) haemodialysis patients showed low antibody response (&amp;lt;100 U/mL), whereas only 5 (10%) non-dialysis patients presented with low antibody response. Patients with an additional infection showed an increased titre of antibodies during follow-up. CONCLUSIONS Our data suggest regular antibody testing as well as a need for booster vaccination in the vulnerable population of haemodialysis patients.