Getting a Booster Too Soon Could Cause This Serious Side Effect, Experts Warn
A new study has found that early shots carry potential risks.
In the U.S., COVID booster shots are expected to be rolled out starting Sept. 20, under guidance from the Biden administration. But while both the Food and Drug Administration (FDA) and Centers for Disease Control and Prevention (CDC) still need to decide on the specific rollout plans, including who will be eligible for additional shots first, it seems clear many people are eager to take the extra protection if they can get it. The CDC reported in early August that more than 1 million people had gotten a third dose already, despite not being authorized to receive a booster shot yet. But experts are now warning that going for a booster too early could put you at risk.
A group of scientists, including two senior FDA officials and the World Health Organization (WHO), published a study in The Lancet on Sept. 13 indicating that booster shots are not yet needed for the general public. In fact, getting these jabs too soon could have negative consequences.
According to the scientists, distributing boosters too early may lead to the potential for more vaccine-induced side effects, like myocarditis. Myocarditis is a rare heart inflammation condition that has affected hundreds of young adults, and it's significantly more common after second doses of the mRNA vaccines than first doses.
"If unnecessary boosting causes significant adverse reactions, there could be implications for vaccine acceptance that go beyond COVID-19 vaccines," the study authors warn. "Thus, widespread boosting should be undertaken only if there is clear evidence that it is appropriate."
According to the study, COVID vaccine effectiveness against infection does appear to wane over time and in light of new variants, but the protection against severe disease persists. The scientists say this is because of the body's complex immune system, which has other defense mechanisms besides antibodies that can protect people from serious illness.
"Protection against severe disease is mediated not only by antibody responses, which might be relatively short lived for some vaccines, but also by memory responses and cell-mediated immunity, which are generally longer lived," the scientists explained.
The study noted that the effectiveness of most vaccines against symptomatic disease did appear to decrease against the Delta variant compared to the Alpha variant. However, "there is still high vaccine efficacy against both symptomatic and severe disease due to the Delta variant," according to the study authors. The CDC reported on Sept. 1o that Moderna is 95 percent effective against hospitalizations amid Delta, while Pfizer and Johnson & Johnson are 77 percent and 65 percent effective, respectively.
"Current evidence does not, therefore, appear to show a need for boosting in the general population, in which efficacy against severe disease remains high," The Lancet study concluded.