Study Provided First “Real-World” Evidence of Effectiveness
Yinong Young-Xu, ScD, director of the Clinical Epidemiology Program at the VAMC in White River Junction, VT (Photo by Geoff Hansen)
WHITE RIVER JUNCTION, VT — When the COVID-19 vaccines rolled out last winter, a unique partnership between the VHA and other federal agencies provided the first real-world evidence—outside of clinical trials—of how well the vaccines were working.
The Food and Drug Administration issued an Emergency Use Authorization (EUA) for Pfizer-BioNTech’s BNT162b2 COVID-19 vaccine on Dec. 11, 2020, and for Moderna’s mRNA-1273 COVID-19 vaccine a week later. But plans for a rollout of the vaccines at the VA had been in the works since summer.
On Dec. 14, the first VA patients received their first dose of a COVID-19 vaccine. By March 7, 2021, 20% of VA’s 6.6 million veterans had received at least one dose of the vaccine from the healthcare system. The findings of a newly published study examining the effectiveness of those early vaccine doses showed impressive results. 1
“In this period, during which the share of SARS-CoV-2 variants Alpha, Epsilon, and Iota had started to increase in the U.S., estimates of COVID-19 vaccine effectiveness against infection, regardless of symptoms, was 95% for full vaccination and 64% for partial vaccination,” the authors wrote recently in JAMA Network Open. Estimated vaccine effectiveness against COVID-19–related hospitalization for full vaccination was 91%, and there were no deaths among veterans who were fully vaccinated.
The case control study found that the VHA’s vaccination effort reached all demographic groups among veterans in the first three months following the shots availability under EUA. Effectiveness of full vaccination against infection was similar for the subgroups studied—non-Hispanic Black, 94%; Hispanic (any race), 83%; non-Hispanic white, 92%; rural, 94%, and urban, 93%.
Results were only slightly lower for veterans who were immunocompromised, the study found. The authors noted that previous clinical trials and observational studies had limited sample size to adequately assess the effectiveness of COVID-19 vaccines for people with underlying medical conditions, although some conditions may predispose individuals to severe consequences from infection. In the current study, however, vaccine effectiveness was 87 % for fully vaccinated veterans who were immunocompromised, which is reassuring, the authors wrote.
Perhaps even more striking than the specific findings is that the collaboration among the VA, FDA and the national Centers for Disease Control and Prevention made the rapid dissemination of the vaccine and positive study findings possible, according to the study’s lead author.
Because the vaccines were administered under EUA, they had not undergone the same testing required for most vaccines, explained Yinong Young-Xu, ScD, director of the Clinical Epidemiology Program at the VAMC in White River Junction, VT, who led the study. “This means they won’t have the full data quite the same way we used to with vaccines, where we tend to run a very long clinical trial, get all the data and then have a full authorization.”
“In the summer of 2020, the FDA said, ‘Could you be ready to study the vaccine as soon as we get the emergency authorization so we can eventually have real-time feedback?’” Young-Xu said. “They wanted to know the vaccines were working in the real world—not just from the clinical trial data.”
Analyze Effectiveness
The way the VA is set up allowed the researchers to both deploy the vaccines and analyze their effectiveness in a diverse population quickly, said Young-Xu. “Our medical records are daily so we have feedback very quickly—whether patients who got vaccinated had breakthrough infections, were they well protect. We have that information.”
He said information was and continues to be relayed to the FDA and CDC regularly. “We were briefing VA leadership every month, and we were briefing FDA officials every two weeks, to get them a real-time picture of how things were working, so no one would be caught off guard.”
The monitoring system set in place with the vaccine’s rollout has continued to be helpful to the FDA, the CDC and the VA. Very early on, in June, the researchers already had the signal that the vaccine effectiveness was going down and that and a booster might be necessary. “We sent that data along with the CDC folks to the White House,” Young-Xu said.
He said monitoring will continue at least for the near future and that he hopes the model established for COVID vaccine surveillance will be employed to study future vaccines and treatments. “We are talking to the FDA folks and the CDC folks and other government agencies to see if this will become routine for the future whenever we rollout on a large-scale vaccine or medication under emergency authorization,” he said.
In the meantime, Young-Xu said he is glad to be a part of an effort that has played such an important role in reducing morbidity and mortality, not only in veterans but in the population as a whole. “I look at data and analyze data and I tell folks whether the vaccines were working or not,” he said. “My children say, ‘Studying data, that’s so boring.’“ But Young-Xu considers it anything but. “On my side, I see everybody comes together—leadership support, FDA, CDC—and everything gets passed onto the White House, onto the COVID-19 Response Team. It’s an incredible feeling to be part of the effort and knowing we are doing things that are really helpful for the country and for the people.”
- Young-Xu Y, Korves C, Roberts J, Powell EI, Zwain GM, Smith J, Izurieta HS. Coverage and Estimated Effectiveness of mRNA COVID-19 Vaccines Among US Veterans. JAMA Netw Open. 2021;4(10). doi:10.1001/jamanetworkopen.2021.28391
