Effectiveness of 2 of 3 COVID-19 Vaccines Used in US Drops Below 50 Percent: Study
Effectiveness of 2 of 3 COVID-19 Vaccines Used in US Drops Below 50 Percent: Study

By Zachary Stieber

The effectiveness of the three COVID-19 vaccines available in the United States has declined in recent months, with protection against infection falling under 50 percent for two of them, according to a new study.

Moderna’s COVID-19 vaccine dropped from 89.2 percent in March to 58 percent in September, researchers found. During the same period of time, Pfizer’s COVID-19 vaccine dropped from 86.9 percent effective to 43.3 percent, and Johnson & Johnson’s shot dropped from 86.4 percent to 13.1 percent.

Dr. Stephen Hahn, the head of the Food and Drug Administration during the final portion of the Trump administration, said last year that the agency wouldn’t authorize COVID-19 vaccines that weren’t at least 50 percent effective against infection.

Researchers also found that the vaccines’ protection against death waned, particularly among older people. Instead of comparing the effectiveness in March and September, though, they used the data to pinpoint the effectiveness from July to October. For those 65 or older, the effectiveness against death was 75.5 percent for Moderna’s vaccine, 70.1 percent effective for Pfizer’s vaccine, and 52.2 percent effective for Johnson & Johnson’s jab.

For younger people, the effectiveness was higher: 84.3 percent for Pfizer’s, 81.5 percent for Moderna’s, and 73 percent for Johnson & Johnson’s.

While early data showed high vaccine effectiveness against both infection and death, “our results suggest vaccines are less effective in preventing infection associated with the Delta variant,” researchers wrote.

While the vaccinated as time wore on faced a higher risk of getting infected with COVID-19 or dying, the unvaccinated were still more likely to contract the illness or die from it, they added.

Researchers with the Public Health Institute, the University of Texas School of Public Health, and the Veterans Affairs Medical Center carried out the research, which was published in the journal Science.

Researchers examined COVID-19 infections and deaths by vaccination status in 780,225 veterans between Feb. 1 and Oct. 1. They used data from the Department of Veterans Affairs and received funding from the Mercatus Center at George Mason University and the University of California Office of the President.

“Our study gives researchers, policy makers and others a strong basis for comparing the long-term effectiveness of COVID vaccines, and a lens for making informed decisions around primary vaccination, booster shots, and other multiple layers of protection, including masking mandates, social distancing, testing and other public health interventions to reduce chance of spread,” Dr. Barbara Cohn, the lead author, said in a statement. The research supports recommendations for many Americans, including all Johnson & Johnson recipients, to get booster shots, she added.

Other studies have shown COVID-19 vaccine effectiveness has waned over time, leading to the booster recommendations from U.S. health authorities, but this was the first to examine all three available in the United States. It also suggested a lower effectiveness against death than many other studies.

COVID-19 is the disease caused by the CCP (Chinese Communist Party) virus.

Limitations of the study included not knowing why or where people were tested; researchers required a person to get tested for COVID-19 to be included in the analysis.

Pfizer, Moderna, Johnson & Johnson, and the U.S. National Institute of Allergy and Infectious Diseases did not respond to overnight requests for comment, and have not appeared to react publicly to the study.

The findings come after two other studies, both preprints, showed vaccine effectiveness against infection decreased over time.

Swedish researchers, using data from nationwide registries, found that Pfizer’s vaccine dropped in effectiveness from 92 percent at day 15 to 30 to 47 percent at day 121 to 180. “From day 211 and onwards no effectiveness could be detected,” they said. The Moderna shot also declined in effectiveness, but retained some protection from day 181 and onwards.

Israeli researchers, meanwhile, extracting data from a nationwide database, found that Pfizer’s vaccine was less effective against both infection and severe disease over time.

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