As the global COVID-19 crisis continues, efforts to find a vaccine for the virus are beginning to show positive results. This week, biotech company Moderna announced that trials of their vaccine resulted in immune responses from all patients. While this is certainly encouraging news, some experts are warning that vaccine immunities may be short-lived. Thanks to the possibility of “disappearing immunity,” one treatment with a vaccine may not be enough.
Back in June, former Harvard Medical professor William A. Haseltine wrote in Forbes about a Nature Medicine study of antibody responses in patients recovering from SARS-CoV-2 — also known as COVID-19. The study found that, 3-4 weeks after the initial detection of the sickness, the majority of patients showed no immune response to the virus.
According to Haseltine, the study’s results “[raise] the possibility that infection by SARS-CoV-2 does not establish long-lasting immunity, at least for those without symptoms or only mildly ill, more than 80% of all those infected by SARS-CoV-2.”
Now, Haseltine says the short lifespan of COVID antibodies may pose an issue for any vaccines, including Moderna’s.
“To proclaim these trials a success is to take for granted that exposing people to viral proteins will trigger a vigorous, long-lasting immune response,” he wrote in a new piece for Forbes. “But studies of the molecular biology of SARS-CoV-2, along with the natural history of the coronavirus family, may offer evidence to the contrary.”
Haseltine pointed to a study from the 1970s on coronaviruses’ ability to re-infect someone who had previously been infected. In the study, patients were voluntarily exposed, contracted colds, then recovered. A year later they received the virus again, leading to the same result.
“These experiments established that protective immunity to the cold-causing coronavirus is short-lived,” wrote Haseltine.
Recent studies of COVID-19 have suggested the same to be true of the current coronavirus. According to Business Insider, researchers in Spain found that antibodies could last just three to five weeks in some cases. Another preliminary study from the UK suggested they could last less than three months.
Hope For a Vaccine
If a COVID-19 vaccine were to be susceptible to such disappearing immunity, Haseltine says, it could mean the sickness will become a “seasonally recurring pandemic.”
However, experts say it wouldn’t necessarily be the end of the line.
“This happens for a lot of vaccines,” vaccinologist Florian Krammer told Business Insider. “It’s not a problem. You can get revaccinated.”
For now, Haseltine has hope that an early version of the vaccine may manage to outwit COVID-19, but also advises caution.
“If we’re not blessed with such good fortune, we must buckle down and recognize that we’re in this for the long haul — and throw our support into the prolonged research effort necessary to ensure success,” he said.