Do the Covid vaccines provide long-lasting protection?
In October, the Centers for Disease Control and Prevention (CDC) recommended that high-risk adults get a second updated Covid vaccine to bolster their protection against the virus. The agency now recommends that people ages 65 and up and those with weakened immune systems get a second dose of the 2024-25 vaccine six months after their first dose, NBC News reports.
Unprecedented frequency of vaccination
No other vaccines are given at such a high frequency, but experts say there’s no reason to believe that the vaccines – and in particular, the mRNA vaccines from Pfizer and Moderna – aren’t effective. However, it’s not the first time the agency has advised or allowed for an additional dose for at-risk groups several months after the first. In the spring of 2022, officials authorized a second booster dose after the initial fall rollout. The same pattern followed in the spring of 2023 and the spring of 2024.
The challenge of long-lasting immunity
Despite the CDC’s recommendation for an additional shot, there’s no evidence that the mRNA vaccines aren’t working as expected, said Akiko Iwasaki, a professor of immunology at the Yale School of Medicine. Rather, there may be something unique to this virus that is preventing people’s bodies from maintaining high levels of immunity.
A recent study from researchers at Emory University found that so-called hybrid immunity – when a person has been both vaccinated and infected with the coronavirus at some point – failed to significantly establish certain long-lasting cells that secrete antibodies. That wasn’t the case for people who had been vaccinated against the flu and tetanus, suggesting, Iwasaki said, that something different is happening with the virus.
The role of the virus’s rapid mutation
The bigger issue, said Dr. Ashish Jha, dean of the Brown University School of Public Health and the former White House Covid-19 response coordinator, is how rapidly the virus mutates, as well as its year-round presence. "The problem here in my mind is not so much with the vaccine but much more with the virus," he said, adding that he supports the updated guidance.
The importance of regular vaccination
The guidelines come amid concerns that waning vaccine immunity, particularly in older adults, may leave them more vulnerable to severe disease and hospitalization. "Topping off your vaccine-induced immunity every six to 12 months is not a bad idea," said E. John Wherry, an immunologist at the University of Pennsylvania. The vaccine bolsters antibody levels, which are the first line of defense against the virus, he added.
A rapidly changing virus
"We look at our flu vaccine strains every year and try to match them up as best we can," said Dr. Anna Durbin, an infectious disease physician and associate professor at the Johns Hopkins University School of Medicine. "It’s changing even faster with Covid – it’s constantly mutating to get the advantage." One reason there aren’t frequent boosters for a virus like measles is because it doesn’t change as rapidly as the coronavirus.
Conclusion
In conclusion, while the mRNA vaccines have shown promising results in providing protection against Covid-19, the virus’s rapid mutation rate and year-round presence pose a significant challenge to long-lasting immunity. Regular vaccination, as recommended by the CDC, is crucial to maintaining protection against the virus, particularly for high-risk individuals. As Dr. Jha noted, "The problem here in my mind is not so much with the vaccine but much more with the virus."
Frequently Asked Questions
- Why are the Covid vaccines given at such a high frequency?
The Covid vaccines, specifically the mRNA vaccines from Pfizer and Moderna, are given at a high frequency due to the rapid mutation rate of the virus. - How does the virus’s rapid mutation rate affect the effectiveness of the vaccines?
The virus’s rapid mutation rate makes it challenging to maintain long-lasting immunity, as the vaccines may not be able to keep pace with the changing strains of the virus. - What is the significance of regular vaccination?
Regular vaccination is crucial to maintaining protection against the virus, particularly for high-risk individuals. The vaccines help to bolster antibody levels, which are the first line of defense against the virus. - Will the Covid vaccines become a universal recommendation for all age groups?
Dr. Jha does not expect the twice-yearly vaccine to become a universal recommendation for all age groups, as the immune system of a 30-year-old is far more robust than that of an 80-year-old.
