Anthony Fauci, director of the National Institute of Allergy and Infectious Diseases for the last three decades and an expert on pandemics for the last four decades, has been optimistic on a vaccine arriving at the end of 2020 or in early 2021, but he has also cautioned the public on their expectations for the effectiveness of any vaccine that is developed.

“The chances of it being 98% are not great, which means you must never abandon the public-health approach,” Fauci told a recent live streamed Q&A hosted by Brown University. “You’ve got to think of a vaccine as a tool to be able to get a pandemic to no longer be a pandemic, but to be something that’s well-controlled.”

“What I’m shooting for is that, with a vaccine and good public-health measures, we can bring it down to somewhere between really good control and elimination,” he told Abdullah Shihipar, a public-health research associate at Brown in the interview. “So that’s what a vaccine is going to do, but it’s not going to do that alone.”

Fauci has said he was hopeful that a coronavirus vaccine could be developed by early 2021, but has previously said it’s unlikely that a vaccine will deliver 100% immunity; he said the best realistic outcome, based on other vaccines, would be 70% to 75% effective. The measles vaccine, he said, is among the most effective by providing 97% immunity.

Reviews of past studies have found that, on average, the flu vaccine is about 50% to 60% effective for healthy adults who are between 18 and 64 years old, according to a review of studies by the Mayo Clinic. “The vaccine may sometimes be less effective,” it said. “Even when the vaccine doesn’t completely prevent the flu, it may lessen the severity of your illness.”

Image Credit:  Jonathan Ernst / Reuters file