COVID-19 cases among vaccinated seniors soared in 2021, according to newly disclosed data that was acquired by U.S. health agencies but not presented to the public.
Humetrix Cloud Services was contracted by the U.S. military to analyze vaccine data. The company performed a fresh analysis as authorities considered in 2021 whether COVID-19 vaccine boosters were necessary amid studies finding waning vaccine effectiveness.
Humetrix researchers found that the proportion of total COVID-19 cases among the seniors was increasingly comprised of vaccinated people, according to the newly disclosed documents.
For the week ending on July 31, 2021, post-vaccination COVID-19 cases represented 73 percent of the cases among people 65 and older, the company found. The elderly were 80 percent fully vaccinated at the time.
Breakthrough infection rates were higher among those who were vaccinated early, the researchers found. They estimated that the rates were twice as high in those who had been vaccinated five to six months prior, when compared to people vaccinated three to four months before.
The breakthrough cases started in January 2021, according to the data.
Protection against hospitalization was also fading, researchers discovered.
In the week ending on July 31, 2021, 63 percent of the COVID-19 hospitalizations in seniors were among the fully vaccinated, according to the documents. The same pattern of weaker protection among people who were vaccinated early was found.
Researchers calculated that the vaccine effectiveness (VE) against infection was just 33 percent while the effectiveness against hospitalization had dropped to 57 percent.
Seniors who previously had COVID-19 and recovered were more likely to avoid hospitalization, the researchers also found. Risk factors included serious underlying conditions such as obesity and being in the oldest age group, or older than 85.
The cohort analysis was completed on 20 million Medicare beneficiaries, including 5.6 million seniors who received a primary series of a COVID-19 vaccine.
“Our observational study VE findings show a very significant decrease in VE against infection and hospitalization in the Delta phase of the pandemic for individuals vaccinated with either the Pfizer or Moderna vaccine for those 5–6 months post vaccination vs. those 3–4 months post vaccination,” Dr. Bettina Experton, Humetrix’s president and CEO, said in a Sept. 15, 2021, email to top U.S. Food and Drug Administration (FDA) officials.
