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Pfizer and Moderna fare better against variants of concern – Dutch research

A recent Dutch comparison of four COVID-19 vaccinations shows that messenger RNA (mRNA) vaccines – Pfizer-BioNTech and Moderna – perform better against the World Health Organisation’s variants of concern (VOCs) than viral vector vaccines: AstraZeneca and J&J.

Although they all effectively prevent severe disease by VOCs, this suggests that people receiving a viral vector vaccine are more vulnerable to infection by new variants.

By March, COVID-19 had caused more than 450m confirmed infections and 6m reported deaths. The first vaccines approved in the US and Europe that protect against serious infection were Pfizer-BioNTech and Moderna, which delivered genetic code, known as mRNA, to the bodies' cells, whereas Oxford/AstraZeneca and J&J/Janssen were viral vector vaccines that used a modified version of a different virus – a vector – to deliver instructions to our cells.

Three vaccines are delivered as two separate injections a few weeks apart, and J&J/Janssen as a single dose.

Marit van Gils, at the University of Amsterdam, and colleagues, took blood samples from 165 healthcare workers, three and four weeks after first and second vaccination respectively, and for J&J/Janssen at four to five and eight weeks after vaccination. Samples were collected before, and four weeks after a Pfizer-BioNTech booster.

Four weeks after the initial two doses, antibody responses to the original SARS-CoV-2 viral strain were highest in recipients of Moderna, followed closely by Pfizer-BioNTech, and were substantially lower in those who received viral vector vaccines. Tested against the VOCs – Alpha, Beta, Gamma, Delta and Omicron – neutralising antibodies were higher in the mRNA vaccine recipients compared with those who had viral vector vaccines.

The ability to neutralise VOCs was reduced in all vaccine groups, with the greatest reduction against Omicron. The Pfizer-BioNTech booster increased antibody responses in all groups with substantial improvement against VOCs, including Omicron.

The researchers caution that their AstraZeneca group was significantly older, because of safety concerns for the vaccine in younger age groups. As immune responses tend to weaken with age, this could affect the results. This group was also smaller because the Dutch government halted use for a period.

Van Gils concluded that: "Four COVID-19 vaccines induce substantially different antibody responses."

Study details

Antibody responses against SARS-CoV-2 variants induced by four different SARS-CoV-2 vaccines in health care workers in the Netherlands: A prospective cohort study.

Marit van Gils, Ayesha Lavell, Karlijn van der Straten, Brent Appelman, Ilja Bontjer, Meliawati Poniman, Judith Burger, Melissa Oomen, Joey Bouhuijs, Lonneke van Vught, Marleen Slim, Michiel Schinkel, Elke Wynberg, Hugo van Willigen, Marloes Grobben, Khadija Tejjani, Jacqueline van Rijswijk, Jonne Snitselaar, Tom Caniels, Alexander Vlaar, Maria Prins, Menno de Jong, Godelieve de Bree, Jonne Sikkens, Marije Bomers, Rogier W. Sanders.

Published in PLOS Medicine on 17 May 2022


Emerging and future SARS-CoV-2 variants may jeopardise the effectiveness of vaccination campaigns. Therefore, it is important to know how the different vaccines perform against diverse SARS-CoV-2 variants.

Methods and findings
In a prospective cohort of 165 SARS-CoV-2 naive health care workers in the Netherlands, vaccinated with either one of four vaccines (BNT162b2, mRNA-1273, AZD1222 or Ad26.COV2.S), we performed a head-to-head comparison of the ability of sera to recognise and neutralise SARS-CoV-2 variants of concern (VOCs; Alpha, Beta, Gamma, Delta and Omicron). Repeated serum sampling was performed 5 times during a year (from January 2021 till January 2022), including before and after booster vaccination with BNT162b2. Four weeks after completing the initial vaccination series, SARS-CoV-2 wild-type neutralising antibody titers were highest in recipients of mRNA-1273, followed by recipients of BNT162b2 (geometric mean titers (GMT) of 358 [95% CI 231–556] and 214 [95% CI 153–299], respectively; p<0.05), and substantially lower in those vaccinated with the adenovirus vector-based vaccines AZD1222 and Ad26.COV2.S (GMT of 18 [95% CI 11–30] and 14 [95% CI 8–25] IU/ml, respectively; p<0.001). VOCs neutralisation was reduced in all vaccine groups, with the greatest reduction in neutralisation GMT observed against the Omicron variant (fold change 0.03 [95% CI 0.02–0.04], p<0.001). The booster BNT162b2 vaccination increased neutralising antibody titers for all groups with substantial improvement against the VOCs including the Omicron variant. We used linear regression and linear mixed model analysis. All results were adjusted for possible confounding of age and sex. Study limitations include the lack of cellular immunity data.

Overall, this study shows that the mRNA vaccines appear superior to adenovirus vector-based vaccines in inducing neutralising antibodies against VOCs four weeks after initial vaccination and after booster vaccination, which implies the use of mRNA vaccines for both initial and booster vaccination.


PLOS Medicine article – Antibody responses against SARS-CoV-2 variants induced by four different SARS-CoV-2 vaccines in health care workers in the Netherlands: A prospective cohort study (Open access)


See more from MedicalBrief archives:


Booster mRNA vaccines wane in effectiveness at 4 months – CDC


CDC: Two-dose mRNA vaccines best at avoiding hospitalisations


Benefits of mix-and-match approach to COVID-19 vaccines


European warning that two strains of Omicron from SA are ’variants of concern’



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