Study: mRNA COVID-19 Vaccines Perform Better Than Viral Vector Vaccines

Research suggests that individuals receiving a vaccine, such as ones from AstraZeneca and Johnson & Johnson, were more vulnerable to infection by new variants.

In a comparison of 4 COVID-19 vaccines, messenger RNA (mRNA) vaccines performed better against the World Health Organization’s variants of concern than viral vector vaccines, according to study results published in PLOS Medicine.1

The research suggests that individuals receiving a viral vector vaccine, such as the AstraZeneca and Johnson & Johnson (J&J) vaccines, were more vulnerable to infection by new variants.1

By March 2022, COVID-19 had caused more than 450 million confirmed infections and 6 million reported deaths1 The first vaccines approved in Europe and the United States protected against serious infection were the Moderna mRNA and Pfizer-BioNTech mRNA vaccines. The mRNA vaccines deliver genetic codes to the body’s cells while viral vector vaccines use a modified version of a different virus to deliver instructions to the body’s cells.1

Investigators took blood samples from 165 health care workers at 3 and 4 weeks after their first and second vaccinations, respectively, and at 4 to 5 weeks after vaccination for the J&J vaccine. Additional samples were collected before and 4 weeks after a Pfizer-BioNTech booster.1

Additionally, 4 weeks after the initial 2 doses, antibody responses to the original SARS-CoV-2 viral strain were highest in recipients of Moderna, followed closely by Pfizer-BioNTech. Investigators found that the response was substantially lower in those who had the viral vector vaccines, AstraZeneca and J&J.1

The neutralizing antibodies were higher in the mRNA vaccine recipients than those who had the viral vector vaccines when tested against the variants of concern, including the Alpha, Beta, Gamma, Delta, and Omicron variants.1

However, the ability to neutralize the variants of concern was reduced in all vaccine groups, with the greatest reduction being against the Omicron variant.1

The Pfizer-BioNTech booster increased antibody responses in all groups with improvement against the variants of concern, including the Omicron variant.1

The group of individuals who received the AstraZeneca vaccine was significantly older, because there are safety concerns for the vaccine in younger age groups, investigators said.1

As immune responses tend to weaken with age, this could have affected the results of the study.1

Additionally, the sample size was smaller, because the Dutch government halted the study for a period of time.1

Approximately 220.7 million individuals are fully vaccinated in the United States, with 102.4 million having the first booster dose and 12.1 million individuals with a second, according to the CDC.2

Additionally, approximately 77.7% of the US population has at least 1 dose of the vaccine, with 95% of individuals older than aged 65 years having 1 dose, according to the CDC.2

Furthermore, approximately 66.5% of the United States population is fully vaccinated, according to the CDC.2

Reference

1. mRNA vaccines like Pfizer and Moderna fare better against COVID-19 variants of concern. Science Daily. News release. May 17, 2022. Accessed May 19, 2022. https://www.sciencedaily.com/releases/2022/05/220517151826.htm

2. Centers for Disease Control and Prevention. COVID Data Tracker. COVID-19 Vaccinations in the United States. Updated May 19, 2022. Accessed May 19, 2022. https://covid.cdc.gov/covid-data-tracker/#vaccinations_vacc-people-onedose-pop-5yr