COVID-19 vaccine booster shots are essential to protect against new variants

The rapidly evolving coronavirus is zigzagging and evading vaccines intended to neutralize it, but researchers appear to have discovered a way to trap it effectively — if only briefly — with booster shots.

COVID-19 vaccine booster shots work well to prevent infections from omicron and its sub-variants such as BA.5, but immune responses wane within three months, according to researchers at the University of Maryland School of Medicine.

“We looked at whether or not these boosters help neutralize the current circulating strains, which are all omicron variants,” Dr. Meagan Deming, an instructor of medicine at UMSOM, told WTOP.

The bottom line, according to Deming: “Getting a booster is essential to protecting from new variants.”

Vaccines stimulate different immune responses simultaneously. Some prevent infection, some lead to less severe outcomes. This research pertains to prevention of infections from vaccines stimulating production of what’s called neutralizing antibody titers.

The findings are part of a larger mix-and-match study conducted at National Institutes of Health-affiliated sites nationwide to explore whether receiving boosters different from the original vaccine affected their effectiveness.

All four vaccines used in the study — from Johnson & Johnson, Pfizer-BioNTech, Moderna and most recently Maryland-based Novavax — were developed before mutations created the omicron variant and its sub variants.

“This paper that just came out in Cell Reports Medicine was to see whether or not boosting still helps neutralize omicron, and how well,” Deming said. “What we found is that nearly every vaccine combination will boost your immunity to the omicron variants really well.”

“They do wane over time, so the longer you go from a boost, the less well it neutralizes and you see that omicron being a little bit more different from the vaccine strain — that decline is a little bit more rapid,” Deming added. “So, It works. It’s not perfect, but it definitely works to improve your response to omicron.”

To help put the findings into perspective, Deming gave examples of the dramatic difference in numbers in a body’s post-infection production of neutralizing antibody titers that bind and block infection.

Vaccinated with no booster:

  • Getting infected with the original SARS-CoV-2 strain virus stimulates a neutralizing antibody titer of 188 that lasts at least six months.
  • Getting infected with omicron BA.5 circulating now stimulates a neutralizing antibody titer of 20, which is barely detectable; the lowest baseline is 10.

Vaccinated with a booster — one month after getting the booster:

  • Getting the original strain virus stimulated a neutralizing antibody titer of over 4,000.
  • Getting infected with omicron BA.5 the neutralizing antibody titer is almost 400.

About three months after the booster:

  • The neutralizing antibody titer against omicron BA.5 goes down to the 80-100 range.

“If you look at people’s neutralization, or their immune response to that Omicron virus, before they got boosted, it was terrible from everyone. But if you get a booster, you get a great immune response. And so that’s really the take-away is that getting a booster is essential to protecting from new variants,” Deming advised.

The data only extends for three months; it’s unclear whether, or when, boosted immune response might go back down to a level of not working.

Deming has a doctorate in microbiology and immunology and is vice chair of the local portion of the study, which is a collaboration between investigators at the University Of Maryland School Of Medicine’s Center for Vaccine Development and Global Health, and the Institute of Human Virology.

The study’s findings will likely inform future decisions about COVID boosters, according to Dr. Kirsten E. Lyke, who is a professor of medicine at UMSOM, as well as the study’s co-chair and site principal investigator.

“Our research demonstrates that novel omicron sub-lineages are becoming less susceptible to the original COVID-19 vaccines and support consideration of more targeted booster options in the future,” Lyke said in a news release.

Kristi King

Kristi King is a veteran reporter who has been working in the WTOP newsroom since 1990. She covers everything from breaking news to consumer concerns and the latest medical developments.

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