Study in France suggests high efficacy of mRNA vaccines against worrisome variants of SARS-CoV-2

A nationwide case-control study conducted in France evaluated the efficacy of 2019 mRNA-based coronavirus disease vaccines (COVID-19) against the original severe acute respiratory syndrome coronavirus 2 (SARS-CoV -2) and its variants, including B.1.1. 7, B.1.351 and P1.

In real pandemic situations, the two-dose regimen of mRNA vaccines showed equivalent protective efficacy against the original virus and the B.1.1.7 variant and slightly reduced efficacy against the B.1.351 and P1 variants. The study has just been published in the journal The Lancet Regional Health – Europe.

context

Less than a year after the emergence of the COVID-19 pandemic, several potent vaccines have been developed against Wuhan’s original strain of SARS-CoV-2. However, with the progression of the pandemic, multiple viral variants with significantly high infectivity appeared and quickly became predominant in many countries around the world. This has raised global concerns about the effectiveness of pre-existing vaccines against newly emerged viral variants.

In real world pandemic situations, most COVID-19 vaccines have shown equivalent efficacy against the original SARS-CoV-2 and variant B.1.1.7, which was first identified in the UK . However, in general, antibodies induced by vaccination or natural infection showed significantly lower efficacy in neutralizing the B.1.351 and P1 variants, which were first identified in South Africa and Brazil, respectively. . The presence of peak E484K and K417N mutations in the B.1.351 variant and peak E484K and K417T mutations in the P1 variant has been attributed to their immune evasion abilities.

In the present study, the scientists evaluated the effectiveness of a two-dose regimen of COVID-19 mRNA-based vaccines against variants circulating mainly in France, which are mostly of SARS-CoV origin. -2 and the variants B.1.1.7, B .1.351, and P1.

Study design

This nationwide case-control study was conducted on 7,288 adults infected with the original SARS-CoV-2 virus, 31,313 with the B.1.1.7 variant, 2,550 with the B.1.351 / P1 variants . In addition, 3,644 uninfected individuals were included as controls. All participants were asked to complete an online survey questionnaire designed to collect information on socio-demographic characteristics, pre-existing health conditions, recent SARS-CoV-2 test results, recent activity-related viral exposures, and vaccination details.

Specifically, the scientists aimed to assess the effectiveness of two mRNA vaccines, BNT162b2 (Pfizer / BioNTech) and mRNA-1273 (Moderna), in real world pandemic settings. However, due to lack of information on the vaccination, they were able to determine the effectiveness of two vaccines separately.

To genetically identify viral variants, all samples positive for SARS-CoV-2 were further analyzed by screening the reverse transcription-polymerase chain reaction (RT-PCR).

Important Notes

Based on the results of the survey, the susceptibility to acquiring an infection with B.1.1.7 or B.1.351 / P1 was relatively higher among male participants, non-health professionals and people with a level of higher education. In addition, a significantly higher susceptibility to contracting B.1.351 / P1 infection was observed in participants even after receiving two doses of mRNA vaccines.

The results of multivariate statistical analysis identified a significant correlation between increased risk of infection and a history of chronic respiratory disease, lower education level, larger household size, having children attending school / daycare in the household or being a health worker. It is important to note that a history of high blood pressure and diabetes has been associated with a lower risk of infection with the B.1.1.7 variants.

Protection against natural infections and vaccination

A recent history of PCR-confirmed SARS-CoV-2 infection (2 to 6 months) was found to be 83% to 88% protective against all viral variants tested. Likewise, a relatively distant history of SARS-CoV-2 infection (over 6 months) was found to be 74% – 84% protective against all viral variants.

The protective efficacy of mRNA vaccines 7 days after the 2^sd the dose was found to be 88% against the original SARS-CoV-2, 86% against the B.1.1.7 variant and 77% against the B.1.351 / P1 variants.

It is important to note that further statistical analysis has identified that ‘being a health care worker’ is a major confounding factor affecting the estimation of vaccine efficacy against SARS-CoV infection. 2.

Importance of the study

Study reveals that mRNA-based COVID-19 vaccines are highly effective in reducing the risk of infection with SARS-CoV-2 and its major variants; thus highlighting the importance of mass vaccination programs in the fight against the COVID-19 pandemic.