Vaccine Effectiveness Studies in the Field

Evans, Stephen; Jewell, Nicholas P.

doi:10.1056/nejme2110605

Cited by 67 publications

(54 citation statements)

References 7 publications

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“…There is little alternative to using observational data to assess vaccine effectiveness against new variants, since further placebo-controlled randomised trials would be unethical (although active comparator trials could still be performed). However, there are numerous biases in observational analyses 22 , particularly if symptomatic testing is non-random and related to perceived efficacy 10 . Potential bias due to such health-seeking behaviour is likely particularly pronounced for mild symptoms, included in many vaccine effectiveness studies using routine symptomatic testing program data.…”

Section: Discussionmentioning

confidence: 99%

Impact of Delta on viral burden and vaccine effectiveness against new SARS-CoV-2 infections in the UK

Pouwels

Pritchard

Matthews

et al. 2021

Preprint

116

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The effectiveness of BNT162b2, ChAdOx1, and mRNA-1273 vaccines against new SARS-CoV-2 infections requires continuous re-evaluation, given the increasingly dominant Delta variant. We investigated the effectiveness of the vaccines in a large community-based survey of randomly selected households across the UK. We found that the effectiveness of BNT162b2 and ChAd0x1 against any infections (new PCR positives) and infections with symptoms or high viral burden is reduced with the Delta variant. A single dose of the mRNA-1273 vaccine had similar or greater effectiveness compared to a single dose of BNT162b2 or ChAdOx1. Effectiveness of two doses remains at least as great as protection afforded by prior natural infection. The dynamics of immunity following second doses differed significantly between BNT162b2 and ChAdOx1, with greater initial effectiveness against new PCR-positives but faster declines in protection against high viral burden and symptomatic infection with BNT162b2. There was no evidence that effectiveness varied by dosing interval, but protection was higher among those vaccinated following a prior infection and younger adults. With Delta, infections occurring following two vaccinations had similar peak viral burden to those in unvaccinated individuals. SARS-CoV-2 vaccination still reduces new infections, but effectiveness and attenuation of peak viral burden are reduced with Delta.

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Section: Discussionmentioning

confidence: 99%

Impact of Delta on viral burden and vaccine effectiveness against new SARS-CoV-2 infections in the UK

Pouwels

Pritchard

Matthews

et al. 2021

Preprint

116

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“…These studies have shown that vaccination dramatically reduces the spread of the virus. It is therefore important to reach a high degree of vaccinated people to reduce the incidence of infection (Evans & Jewell, 2021). Above a certain threshold of the proportion vaccinated in the population, general immunity can be achieved, known as herd immunity (Fine et al, 2011).…”

Section: Introductionmentioning

confidence: 99%

Coronavirus vaccination rates in cultural areas in Germany

Spahn

Hipp

Richter

et al. 2021

Preprint

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Vaccination rates can provide useful information about potential risks of infection in a given population. In this study, the vaccination rates and attitudes toward vaccination in cultural sectors, i.e. music areas, have been investigated. In total, 4341 persons in four different areas including visitors of classical music and musicals as well as professional and amateur musicians participated in this survey. Results showed rates of 86% recovered or vaccinated at least once and 54.5% fully vaccinated. These vaccination rates were considerably higher compared to the general population. Vaccination hesitancy was half that of the general population at 6.4%. The findings of this large sample indicate that in the field of music culture there is a high vaccination rate and a low rejection of vaccination on the part of the audience and the performers. The risk of infection can therefore be assumed as very low and the opening of cultural events can thus be recommended.

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“…The COVID-19 vaccines from Pfizer/BioNTech (BNT162b2) and Moderna (mRNA-1273) manufacturers based on mRNA encoding the SARS-CoV-2 full-length spike (S) protein have shown vaccine efficacies of 95% and 94%, respectively, against COVID-19 disease after two doses in phase 3 trials [2,3]. Both vaccines induce good immunogenicity [4][5][6][7][8][9][10][11] and excellent effectiveness in real world population after two doses [12][13][14][15] but lower effectiveness against variants of concern (VoC) after one dose [12,14,15] and against the Delta variant following two doses [16].…”

Section: Introductionmentioning

confidence: 99%

Determinants of early antibody responses to COVID-19 mRNA vaccines in exposed and naive healthcare workers

Moncunill

Aguilar

Ribes

et al. 2021

Preprint

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Background Two doses of mRNA vaccination have shown >94% efficacy at preventing COVID-19 mostly in naive adults, but it is not clear if the second dose is needed to maximize effectiveness in those previously exposed to SARS-CoV-2 and what other factors affect responsiveness. Methods We measured IgA, IgG and IgM levels against SARS-CoV-2 spike (S) and nucleocapsid (N) antigens from the wild-type and S from the Alpha, Beta and Gamma variants of concern, after BNT162b2 (Pfizer/BioNTech) or mRNA-1273 (Moderna) vaccination in a cohort of health care workers (N=578). Neutralizing capacity and antibody avidity were evaluated. Data were analyzed in relation to COVID-19 history, comorbidities, vaccine doses, brand and adverse events. Findings Vaccination induced robust IgA and IgG levels against all S antigens. Neutralization capacity and S IgA and IgG levels were higher in mRNA-1273 vaccinees, previously SARS-CoV-2 exposed, particularly if symptomatic, and in those experiencing systemic adverse effects. A second dose in pre-exposed did not increase antibody levels. Smoking and comorbidities were associated with lower neutralization and antibody levels. Among fully vaccinated, 6.3% breakthroughs were detected up to 189 days post-vaccination. Among pre-exposed non-vaccinated, 90% were IgG seropositive more than 300 days post-infection. Interpretation Our data support administering a single-dose in pre-exposed healthy individuals. However, heterogeneity of responses suggests that personalized recommendations may be necessary depending on COVID-19 history and life-style. Higher mRNA-1273 immunogenicity would be beneficial for those expected to respond worse to vaccination. Persistence of antibody levels in pre-exposed unvaccinated indicates maintenance of immunity up to one year.

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Vaccine Effectiveness Studies in the Field

Cited by 67 publications

References 7 publications

Impact of Delta on viral burden and vaccine effectiveness against new SARS-CoV-2 infections in the UK

Impact of Delta on viral burden and vaccine effectiveness against new SARS-CoV-2 infections in the UK

Coronavirus vaccination rates in cultural areas in Germany

Determinants of early antibody responses to COVID-19 mRNA vaccines in exposed and naive healthcare workers

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