Long-Term Questions Remain About COVID-19 Vaccine Durability, Efficacy

Although safety and efficacy have been proven, a few questions still remain about how long the vaccines will be effective and whether they prevent asymptomatic infection.

Although the available vaccines for coronavirus disease 2019 (COVID-19) have proven their safety and efficacy in order to obtain FDA approval, a few questions still remain about how long the vaccines will be effective and whether they prevent asymptomatic infection, according to Michael Haydock, senior director of cardiovascular, metabolic, and infectious diseases content at Informa Pharma Intelligence.

Thus far, the FDA has approved vaccines by Moderna as well as Pfizer and BioNTech, and a vaccine by AstraZeneca has been approved in the UK. Haydock said he believes durability is the primary remaining question, although it can only be answered by monitoring antibody levels over time. He said the hope is for at least 1 year of protection based on data collected in clinical trials.

Haydock added that other questions still to be answered include long-term safety, whether the vaccines are safe and efficacious in children, and whether the vaccines prevent asymptomatic infections as well as symptomatic. Establishing whether vaccines prevent asymptomatic infections is especially important, Haydock said, because individuals who are asymptomatically harboring the virus could still spread it to others.

“If you can stop infection completely, that’s the ideal,” Haydock said. “That hasn’t caused any implications because then you’re protecting people who aren’t vaccinated yet, either just because they haven’t had the chance or they can’t be for whatever reason.”