Covid-19: Vets Study Finds mRNA-1273 Covid Vaccine Slightly More Effective than BNT162b2

The mRNA-1273 vaccine (Moderna) proved to be more effective than the BNT162b2 vaccine (Pfizer-BioNTech) for preventing severe Covid-19 in a real-world use comparison trial involving U.S. veterans, although both vaccines were highly efficacious for preventing hospitalization, ICU admission, death, and other bad outcomes.

Close to 440,000 mostly older, and mostly male veterans were followed for 24 weeks after vaccination with either the mRNA-1273 vaccine or the BNT162b2 vaccine between January and May of this year.

BNT162b2 recipients were found to have a 27% higher risk of documented SARS-CoV-2 infection and a 70% higher risk of Covid-19-related hospitalization compared to mRNA-1273 recipients over the follow-up, during a time when the SARS-CoV-2 Alpha variant was still predominant in the United States.

But the excess number of hospitalization events for Covid-19 among the BNT162b2 recipients compared to the mRNA-1273 recipients was small (0.55 per 1,000 people), and the risk of death was almost identical between the two vaccination groups.

The study findings were published online December 1 in The New England Journal of Medicine.

While the findings revealed an apparent efficacy benefit for the mRNA-1273 vaccine, the study did not assess the relative safety of the two vaccines.

“Head-to-head comparisons of the BNT162b2 and mRNA-1273 vaccines for safety outcomes are lacking, but early randomized trials identified only transient local and systemic reactions (e.g. pain at the injection site and headache) that are common among other vaccines, and observational studies and surveillance efforts have confirmed the safety of thee vaccines for the population overall,” wrote researcher Barbra Dickerman, PhD, of the Harvard T.H. Chan School of Public Health, Boston, and colleagues.

“Given the high effectiveness and the safety profile of both mRNA vaccines, either vaccine is strongly recommended,” they added.

The researchers emulated a target trial using electronic health records from U.S. veterans who received a first dose of either mRNA vaccine between Jan. 4-May 14, 2021. Vaccine recipients were matched 1:1 according to their risk factors, and study outcomes included documented severe SARS-CoV-2 infection, symptomatic Covid-19, Covid-19 hospitalization, ICU admission, and death.

Each vaccine group included 219,842 people, 93% of all vaccine recipients were male, and 90% were age 50 years or older.

Over 24 weeks of follow-up during early 2021, the estimated risk of documented infection was 5.75 events/1,000 persons (95% CI, 5.39-6.23) in the BNT162b2 group and 4.52 events/1,000 persons (95% CI, 4.17-4.84) in the mRNA-1273 group.

The excess number of events/1,000 persons for BNT162b2 recipients compared to the mRNA-1273 recipients was:

• 1.23 (95% CI, 0.72 to 1.81) for documented infection.
• 0.44 (95% CI, 0.25-0.70) for symptomatic Covid-19.
• 0.55 (95% CI, 0.36-0.83) for hospitalization for Covid-19.
• 0.10 (95% CI, 0.00-0.26) for ICU admission for Covid-19.
• 0.02 (95% CI, −0.06 to 0.12) for death from Covid-19.

When the researchers examined the health records of veterans vaccinated between July 1 and Sept. 20 of this year, when the Delta variant had replaced the Alpha variant as the predominant SARS-CoV-2 strain, the mRNA-1273 vaccine continued to show greater efficacy.

Over 12-weeks of follow-up in the later analysis, the excess risk of documented infection was 6.54 events/1,000 people among the BNT162b2 vaccine recipients (95% CI, -2.58 to 11.82).

In a commentary published with the study, NEJM editor in chief Eric J. Rubin, MD, and deputy editor Dan Longo, MD, wrote that the findings add to the evidence showing slight variations in effectiveness for the two mRNA vaccines.

“For any given person, the difference in vaccine efficacy between BNT162b2 and mRNA-1273 is unmeasurable,” they wrote. “In the United States, the availability of two mRNA vaccines has allowed us to ramp up vaccination efforts far more quickly than if we had only one.”

They added that the urgent need to improve vaccine coverage in much of the rest of the world will “require both mRNA vaccines, along with others that are currently being developed and deployed. Even if they are less able to protect against infection, many of the other available vaccines do a very good job of protecting against severe disease. Moreover, the study by Dickerman et al. gives us no idea how the vaccines will compare after an additional booster dose. So the lesson we take away is not about differences—it’s about similarities. We are lucky to have such good options. Vaccination with any vaccine is far better than remaining unprotected. The message is that the best vaccine is the one that’s available.”

Study limitations include its observational, non-randomized design, the possibility of outcome misclassification in patients who received care outside the VA health care system, and the predominance of men and older patients.

1. The mRNa-1273 vaccine proved to be more effective than the BNT162b2 vaccine for preventing severe Covid-19 in a real-world use comparison trial involving U.S. veterans.

2. The excess number of hospitalization events for Covid-19 among the BNT162b2 recipients compared to the mRNA-1273 recipients was small (0.55 per 1,000 people), and the risk of death was almost identical between the two vaccination groups.

Salynn Boyles, Contributing Writer, BreakingMED™

Cat ID: 125

Topic ID: 79,125,730,933,125,190,31,926,192,927,725,928,925,934