Study shows dramatic decline in effectiveness of all three COVID-19 vaccines over time
The Delta variant of coronavirus became the predominant strain in the United States. All three COVID-19 vaccines were no longer effective. According to a new study, vaccine efficacy was reduced by between 35% to 85% among veterans.
Researchers dug through nearly 800,000.00 U.S. veteran records and found that all three vaccines could prevent infection.
However, this changed drastically over the next six-months.
Moderna’s two-dose COVID-19 (or Moderna) vaccine, which was supposed be 89% effective but only 58% in March, was effective at the end.
Pfizer and BioNTech shot effectiveness decreased from 87% down to 45% over the same period.
Most strikingly, Johnson & Johnson’s single dose vaccine saw its protective power drop from 86% down to only 13% in six months.
The findings were published in Science on Thursday.
The three vaccines held up better in their ability to prevent COVID-19 deaths, but by July — as the Delta variant began to drive a three-month surge of infections and deaths — the shots’ effectiveness on that score also revealed wide gaps.
The rate of COVID-19 death in those 65 and older who received the Moderna vaccination was 76% lower among veterans who had been inoculated.
Older veterans who received the Pfizer BioNTech shot and had a breakthrough illness were 70% less likely not to die than their unvaccinated counterparts.
Older vets who received a single shot of J&J were 52% less likely than those who did not get shots to die from a breakthrough infection.
For veterans under 65, the Pfizer-BioNTech and Moderna vaccines provided the best protection against a fatal case of COVID-19, at 84% and 82%, respectively. J&J vaccine inoculated younger veterans with breakthrough infections was 73% less likely to succumb to COVID-19 than those who had not been vaccinated.
Representatives of Johnson & Johnson did not respond immediately to inquiries to discuss the findings.
The Centers for Disease Control and Prevention recommended booster shots for every person who received the Johnson & Johnson Vaccine at least 2 months ago.
boosters are also recommended six-months after the second dose of Moderna or Pfizer vaccinations for all 65+; people with serious medical conditions that could make them more susceptible to COVID-19; anyone who lives in a group setting or in a nursing home; and those who work in high risk settings such as prisons and hospitals.
In addition, all people with compromised immune systems are advised to get a booster shot if it’s been at least 28 days since their vaccine took full effect.
With millions of vaccinated Americans pondering whether they need a boost, the new study offers the most comprehensive comparison yet of how the three vaccines have performed across the nation this year.
It tracked 780.225 veterans of the U.S. Armed Forces from February 1 through October 1. Nearly 500,000 had been vaccinated while only 300,000 hadn’t.
They were all from different parts of the country and were provided with healthcare by the Veterans Affairs’ unified system. It provides healthcare to 2.7% the U.S. population. Although the ethnicity and racial makeup of the participants in the study varied, the record-keeping system used by researchers was uniform.
This was because the veterans in the study were six times more than women. They were also more senior than expected: 48% were over 65, 29% were 50-64, and 24% were below 50.
While older veterans were more likely not to die than younger ones during the study period (see Figure 1), the decline in vaccine protection against illness or death was evident in both young- and old vets.
The study was conducted in collaboration with the Public Health Institute of Oakland, Veterans Affairs Medical Center of San Francisco, and University of Texas Health Science Center.
Dr. Barbara Cohn, lead author of the study, stated that in addition to comparing COVID-19 vaccines the analysis gives “an insight into making informed decisions about primary vaccination, booster shots and other multiple layers protection.” That includes mask mandates, coronavirus testing and other public health measures aimed at countering viral spread.
The authors stated that strong evidence points to the decline in vaccine power should encourage states and regions with high vaccination rates to retain mask mandates. The findings support the CDC’s recommendation that all J&J vaccine recipients receive a booster.
The study concluded that the Delta variant, which drove a wave of infections and deaths across the country this spring and summer, was likely the factor that most eroded the protection of vaccines.
Another researcher has found similar evidenceof decreasing vaccine effectiveness. They have also suggested that the immune system’s defenses against SARS/CoV-2 just fade over time and that waning vaccination effectiveness could have occurred with or without the introduction of a more transmissible strain.
This story was originally published in Los Angeles Times.