Key Takeaways

Even if you are fully vaccinated against COVID-19, getting a booster shot is still recommended because it will help protect you against severe illness and poor outcomes if you do get sick.

A large study published in theBMJthat involved over 893,000 adults recently found that the monovalent, or original, mRNAboostersprotect against moderate and severe COVID for about four to five months before it starts to wane.

“This study resoundingly reinforces what we have seen in every other study in terms of the short- and longer-term health benefits and overall safety of staying up to date with COVID vaccination,”Mark Loafman, MD, MPH, a family physician and chair of the Family and Community Medicine Department at Cook County Health, told Verywell.

The study’s findings present strong evidence about the effectiveness of booster shots and the need to administer additional boosters to maintain a high level ofimmunity against COVID.

How Long Will Immunity Last With the New COVID Bivalent Booster?

What Boosters Can and Cannot Do

Loafman said that the study expanded on the original vaccine research trials and provided more details on the effectiveness of the third and fourth COVID vaccine shots in various subgroups.

For example, the study showed that the effectiveness of the Pfizer or Moderna boosters both waned in adults, regardless of how old they were. Vaccine effectiveness also tended to be lower for people who wereimmunocompromised, and its waning was more evident.

Interestingly, booster vaccines appeared to be particularly good at preventing severe outcomes. The study reported that the protection against moderate disease waned more than that against severe disease.

“First, it’s a very large study which means it has a lot of statistical power to base conclusions on,”Andy Pekosz, PhD, a virologist and the vice-chair of the Department of Molecular Microbiology and Immunology at the Johns Hopkins Bloomberg School of Public Health, told Verywell. “Second, while vaccine efficacy against hospitalization waned, it was still at a pretty good level.”

However, much like the primary vaccine doses, booster shots cannot completely prevent people fromgetting infected with COVID.

“Omicron, in particular, evaded a good portion of vaccine-induced immunity, which makes the vaccine efficacy numbers get lower faster,” said Pekosz. “If a variant more closely related to the vaccine had been circulating at the time of the study, I expect we could have seen a higher vaccine efficacy.”

What We Know So Far About the New COVID-19 Booster Side Effects

How Effective Are Bivalent Boosters?

The study authors analyzed data from January 2021 to July 2022, which covered the periods when the Delta andOmicron variantsof the COVID virus were dominant.

Pekosz said that the currentbivalent boostersare a better match to the currently circulating variants, so “the protection should be stronger than what is seen in this study.”

A recent study published in theNew England Journal of Medicinereported that a bivalent vaccine with the Omicron BA.1 spike protein provided protection against COVID for at least a month. The shot also prompted a higher antibody response againstearlier COVID variants, including Alpha, Beta, Gamma, and Delta.

It’s important to keep in mind that these results are from clinical research that’s ongoing, and more data will come out over the long term. That said, the authors of the current study do believe that the findings show the benefit of bivalent boosters.

What You Need to Know About the Updated COVID-19 Boosters

It’s likely that the protection from bivalent boosters may last as long as the monovalent boosters, but Loafman said that “we need a few more months of large-scale observation following bivalent booster administration to know for sure.”

For now, take note of whether you’re up to date with your COVID boosters. If it’s been at least two months since your last COVID vaccine dose, it’s recommended that you get the updated bivalent booster to have better protection against the Omicron variants BA.4 and BA.5.

What This Means For YouResearch is showing that COVID-19 boosters are effective at providing protection against severe disease, but the effectiveness wanes after about four to five months. To stay protected, make sure that you’re keeping up to date with your vaccinations andget boostedwhen you are eligible.

What This Means For You

Research is showing that COVID-19 boosters are effective at providing protection against severe disease, but the effectiveness wanes after about four to five months. To stay protected, make sure that you’re keeping up to date with your vaccinations andget boostedwhen you are eligible.

The information in this article is current as of the date listed, which means newer information may be available when you read this. For the most recent updates on COVID-19, visit ourcoronavirus news page.

2 SourcesVerywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read oureditorial processto learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.Ferdinands JM, Rao S, Dixon BE, et al.Waning of vaccine effectiveness against moderate and severe covid-19 among adults in the US from the VISION network: test negative, case-control study.BMJ. 2022;379:e072141. doi:10.1136/bmj-2022-072141Chalkias S, Harper C, Vrbicky K, et al.A bivalent Omicron-containing booster vaccine against Covid-19.N Engl J Med. 2022;387(14):1279-1291. doi:10.1056/NEJMoa2208343

2 Sources

Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read oureditorial processto learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.Ferdinands JM, Rao S, Dixon BE, et al.Waning of vaccine effectiveness against moderate and severe covid-19 among adults in the US from the VISION network: test negative, case-control study.BMJ. 2022;379:e072141. doi:10.1136/bmj-2022-072141Chalkias S, Harper C, Vrbicky K, et al.A bivalent Omicron-containing booster vaccine against Covid-19.N Engl J Med. 2022;387(14):1279-1291. doi:10.1056/NEJMoa2208343

Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read oureditorial processto learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.

Ferdinands JM, Rao S, Dixon BE, et al.Waning of vaccine effectiveness against moderate and severe covid-19 among adults in the US from the VISION network: test negative, case-control study.BMJ. 2022;379:e072141. doi:10.1136/bmj-2022-072141Chalkias S, Harper C, Vrbicky K, et al.A bivalent Omicron-containing booster vaccine against Covid-19.N Engl J Med. 2022;387(14):1279-1291. doi:10.1056/NEJMoa2208343

Ferdinands JM, Rao S, Dixon BE, et al.Waning of vaccine effectiveness against moderate and severe covid-19 among adults in the US from the VISION network: test negative, case-control study.BMJ. 2022;379:e072141. doi:10.1136/bmj-2022-072141

Chalkias S, Harper C, Vrbicky K, et al.A bivalent Omicron-containing booster vaccine against Covid-19.N Engl J Med. 2022;387(14):1279-1291. doi:10.1056/NEJMoa2208343

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