- People who previously were infected with Covid should eventually get vaccinated against the disease, Dr. Scott Gottlieb told CNBC.
- Natural immunity is robust at first, but it is likely "not going to last in perpetuity," the former FDA chief said Wednesday.
- "At some point, those individuals are going to need to get vaccinated," he said.
People who previously were infected with Covid-19 should eventually get vaccinated against the disease because their immunity protection will likely wane over time, Dr. Scott Gottlieb told CNBC on Wednesday.
"The immunity conferred by natural infection seems to be robust and seems to be durable. We know it lasts at least six months, probably longer," the former commissioner of the Food and Drug Administration said on "Squawk Box."
"My hunch is it's not going to last in perpetuity. At some point, those individuals are going to need to get vaccinated," added Gottlieb, who now serves on the board of vaccine maker Pfizer.
A key question remaining about natural immunity is whether having a more severe case of Covid, compared with someone who remained asymptomatic, for example, leads to higher-quality protection.
"With SARS and MERS, we saw people who got more sick ended up having more durable immunity. We don't know if that's the case with this SARS-CoV-2 virus, but it might be," Gottlieb said, referring to two other types of coronaviruses — severe acute respiratory syndrome and Middle East respiratory syndrome — that caused outbreaks in multiple countries.
SARS was first detected in 2003, while MERS was initially reported in 2012, according to the World Health Organization. The SARS and MERS outbreaks were not nearly as widespread as SARS-CoV-2, the virus that causes Covid, with very few U.S. cases. They caused a limited number of deaths when compared with Covid. However, they were both far more deadly.
Gottlieb's comments Wednesday follow recent studies that have examined immunity from prior Covid infections versus those who received a vaccine for the disease.
One study conducted in Israel found that natural infection offered "longer lasting and stronger protection" against the highly transmissible coronavirus delta variant than Pfizer's two-dose Covid vaccine. It has not yet been peer-reviewed.
By contrast, a study in the U.K., which also hasn't been peer-reviewed yet, arrived at a different conclusion. "Effectiveness of two doses remains at least as great as protection afforded by prior natural infection," the researchers wrote. Unlike in the Israeli paper, participants in this study included recipients of AstraZeneca's and Moderna's two-dose vaccines, in addition to Pfizer.
"I think on the balance it's unclear whether vaccine-induced immunity is better, slightly better, slightly worse, than" natural immunity, Gottlieb said.
Pfizer's vaccine was fully approved last month by the FDA, which is still considering the application of Moderna, currently under an emergency use authorization in the U.S., for full approval. AstraZeneca did not receive an EUA in the U.S. Johnson & Johnson's single shot, the only other vaccine given in the U.S., was cleared for emergency use. J&J has yet to apply for full FDA approval.
Gottlieb acknowledged that data shows vaccine protection declines over time, as well. The U.S. is currently administering booster shots to people who have weakened immune systems to counteract that — and later this month, a broader swath of the population will become eligible for an additional vaccine dose.
"You can redose a vaccine. You don't want to redose an infection," said Gottlieb, who led the FDA from 2017 to 2019 in the Trump administration. "To acquire infection-induced immunity you have to actually get the infection which is something that we want to try to actively avoid, so getting a vaccine has a lot of elegant attributes in that regard."
Nearly 62% of the U.S. population has received at least one Covid vaccine dose, while 52.4% are fully vaccinated, according to data compiled by the Centers for Disease Control and Prevention.
Health officials, politicians and business leaders alike have been urging more Americans to receive a Covid vaccine. A number of companies and other entities such as universities are adopting strict vaccine requirement policies, in hopes of convincing hesitant people to take the lifesaving shot.
Some unvaccinated Americans may believe their previous coronavirus infection offers adequate protection against the disease, so they do not feel a sense of urgency to get the vaccine.
However, Gottlieb's remarks Wednesday add to his previously stated view that people who have been infected and then get vaccinated have "the best of both worlds."
"At least with one dose, you do develop a broad, very deep, very durable immunity based on the data that we've seen so far," Gottlieb said July 6 on CNBC. "So, there's still a lot of compelling reasons why you'd want to get vaccinated even if you've been previously infected."
Disclosure: Scott Gottlieb is a CNBC contributor and is a member of the boards of Pfizer, genetic testing start-up Tempus, health-care tech company Aetion and biotech company Illumina. He also serves as co-chair of Norwegian Cruise Line Holdings' and Royal Caribbean's "Healthy Sail Panel."