Early in the pandemic, vaccines were often seen as the savior that would defeat COVID and return life to normal. Unfortunately, it hasn’t worked out that way.
“The vaccine strategy has been extremely effective in reducing the risk of progression to severe disease, but current vaccines do not prevent transmission of the coronavirus,” said Ziyad Al-Aly, a clinical epidemiologist at Washington University in St. Louis. .
Although the fact that vaccinated people can be reinfected with COVID has become a scientific consensus, how these reinfections compare in severity to initial infections has been less clear, until now.
Al-Aly is the lead author of a new study published Thursday that shows reinfection leads to a higher risk of health problems than the initial infection.
Coronavirus reinfection increases health risks
the paperpublished in Natural medicine, shows that becoming infected with COVID a second time is associated with an increased risk of acute problems in the 30 days after infection. It also showed a higher risk of post-acute problems during the long phase of COVID.
“We’re not advocating draconian measures, but going into the winter season, policymakers and individuals can do things within their power to try to reduce risk at the population level,” Al-Aly told DW.
The largest study of coronavirus reinfection to date
Al-Aly, who also works as a clinician, began seeing patients who had been infected with COVID multiple times, even if they had been vaccinated.
“A lot of people thought they would have some kind of superimmunity against the virus and a second infection wouldn’t matter. We thought we didn’t really know if that was true, so we wanted to study if reinfection really matters,” he said.
The authors used the US Department of Veterans Affairs Health Care Database to investigate risks related to COVID reinfection. The database included a total of more than 5.3 million people, including 40,947 people who had had two or more COVID infections.
Overall, the study found that COVID reinfection overwhelmingly increases adverse health risks.
Compared with no reinfection, having COVID a second time doubled the risk of death and tripled the risk of hospitalization.
Furthermore, repeated coronavirus reinfections increased the risk of adverse health effects with each reinfection.
“What a two- to three-fold increase in risk means for an individual is difficult to determine. But the underlying message is that people need to be aware that reinfection carries a risk, and it’s not trivial,” Al said. Aly.
The impact of the vaccine is still unclear
The study did not include some important elements, say outside experts.
“This study does not mention the impact of vaccines on reinfection risks,” said Beate Kampmann, a professor of pediatric infection and immunity at the London School of Hygiene and Tropical Medicine.
According to Kampmann, understanding the impact of vaccines on COVID reinfection could be crucial for monitoring health outcomes.
“Reinfection data can also inform us about ways to better protect people against coronavirus,” he said. “For example, if we better understand the immune response to reinfection, we can deduce what a vaccine needs to accomplish.”
“However, this could change if we see new variants or a drastic decline in immunity. We need more longitudinal studies to examine this,” Kampmann added.
Database of white men could limit meaning to wider audience
Kampmann also noted that the study primarily included older white American men, more than 90% of which means it might be difficult to extrapolate the data to other demographics.
The study authors also acknowledge this limitation, but stated that they adjusted the risk ratios for age, sex and race in the study.
“There may be people at higher risk than others, but the average risk we measured was independent of the underlying characteristics of the population. Due to the size of the study, the representation of the different groups is probably valid for the population,” Al-Aly said. . .
Is a new vaccine strategy needed for true long-term protection?
Experts have long called for a revamped vaccination strategy to provide better and longer-lasting protection against COVID.
Al-Aly is one of those calling for a vaccination strategy 2.0, stating that the biggest challenge is creating vaccines that prevent transmission of the coronavirus and provide protection that lasts for several years.
“This is what we need to do to truly adapt to the virus, otherwise we will be wearing masks for the next hundred years,” he said.
On the plus side, science and technology are already there to do this. Nasal vaccines that produce mucosal immunity to block transmission for several years are currently under development, with promising results.
“Now we need governments to fund and develop the technology to bring it to the public,” Al-Aly said.
Edited by: Clara Roth