Bivalent booster efficacy and covering vaccination rates among seniors

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The CDC is urging everyone, especially older adults (65+) to get their bivalent COVID-19 booster as soon as possible. Among hospitalized seniors, the updated booster provided significant additional protection against hospitalization compared with being unvaccinated or only receiving monovalent vaccination. During the holiday season, in particular, they’re also encouraging all adults 65 and older to further protect themselves from infection by masking and social distancing when possible.

Early findings show that a bivalent booster dose provided strong protection against COVID-19–associated hospitalization in older adults and additional protection among those with previous monovalent-only mRNA vaccination, the report said.

Researchers in the Investigating Respiratory Viruses in the Acutely Ill (IVY) Network, which included 22 participating hospitals in 18 states, assessed the effectiveness of a bivalent booster dose against unvaccinated older adults and among those who received at least two doses of monovalent mRNA vaccine against COVID-19–associated hospitalization among immunocompetent adults aged 65 and older. 

Between September 8 and November 30, 2022, a total of 798 older adults admitted for COVID-19–like illness were eligible for inclusion in this test-negative design, case-control analysis. All received testing for SARS-CoV-2. Those receiving a positive result within 10 days of illness onset and three days of hospitalization were considered case patients; those testing negative during the same interval were classified as control patients. You may recall that Omicron BA.5 or BQ.1/BQ.1.1 were predominant at that time.

The bivalent booster, combined with the original vaccine regimen, was 84% more effective in preventing COVID-19-related hospitalizations among older people compared with being unvaccinated and was 73% more effective in preventing COVID-19 hospitalizations among seniors who had only received two or more monovalent vaccines. 

In a second study, CDC researchers found that bivalent booster doses provided additional protection against COVID-19–associated emergency department/urgent care visits and hospitalizations in people who previously received two, three, or four monovalent vaccine doses in the VISION network — comprised of nine hospitals in 11 different states. This study looked at all adults, not just those 65 and older. 

Effectiveness in preventing ED or urgent care visits was 56% compared with unvaccinated people, and 31% to 50% among those who received two or more monovalent vaccines, depending on when they received their last dose.

“We now have nine lab studies and one real-world study showing the fall boosters provide greater protection against infection and transmission, broader protection and longer protection against infection and severe disease, even just by a few months,” wrote epidemiologist Katelyn Jetelina, M.P.H., Ph.D. in her recent newsletter.

We didn’t know whether they provided additional protection against severe disease and hospitalization. We now have three real-world analyses, and things are looking good,” she said.

Still, 64% of seniors in the U.S. have not had the most recent booster, noted Eric Topol, M.D. director of the Scripps Research Translational Institute, writing on social media. Yet, seniors account for most of the increased hospitalizations

CDC’s COVID data tracker shows 2,638 people 70 and older were hospitalized for COVID-19, for the seven days ending December 14. That’s up from 2,566 the prior week and about three times higher than most other age groups. Compounding the problem, less than half of nursing home residents and only about 22% of nursing home staff are up to date on their boosters.

We’re doing a “terrible” job in protecting vulnerable older people, Topol told the Associated Press.

Journalists reporting on COVID cases and hospitalizations in their communities, especially among those 65 and older might want to ask:

  • What county, city, and state officials are doing to encourage more people to get the bivalent booster? 
  • Is masking making a comeback? 
  • Are local hospitals, including EDs, prepared for a projected wave of new cases following the holidays?
  • Why are so many people still vaccine hesitant?
  • What local nursing homes are doing to help protect their residents and staff? 
  • Have any reinstated testing requirements for staff, visitors, or vendors? 
  • How are they handling new cases?

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