COVID-19 vaccines show promising results, but challenges ahead

This month, companies Pfizer and Moderna announced promising results for their COVID-19 vaccines, with early data showing both to be highly effective in preventing infection.

The speed of development and level of efficacy of the two vaccines is “remarkable,” said Margaret Hamburg, MD, former commissioner at the U.S. Food and Drug Administration, during the latest installment of the COVID-19 Conversations webinar series, “Vaccine Update: Development, Approval, Allocation and Distribution in the U.S.” 

If proven safe, the vaccines could be authorized for broader use by year’s end, with tens of millions of doses ready to distribute to front-line workers, as well as others by the spring. The news offers some hope, as the U.S. experiences a record surge in COVID-19 cases and deaths. 

Close to a dozen other vaccines are also in the final stages of clinical testing, and more are under development. That’s important because the number of vaccine doses needed to inoculate an estimated 7 billion people worldwide is enormous, especially given that the Pfizer and Moderna vaccines require two doses to be effective — the former 21 days apart and the latter 28 days.

“The goal is to get as many vaccines as we can licensed (by FDA),” said panelist Larry Correy, MD, an expert in virology, immunology and vaccine development and former president and director of Seattle’s Fred Hutchinson Cancer Research Center.

In April, he and Anthony Fauci, MD, director of the National Institute of Allergy and Infectious Diseases, developed a collaborative framework for vaccine development – the National Institutes of Health’s COVID-19 Prevention Network. The effort builds on existing expertise and coronavirus research and incorporates clinical trials of different kinds of vaccines for rapid evaluation and scalability.

Pfizer’s and Moderna’s late-stage vaccine trials included large-scale efficacy tests involving 30,000 people each, among them members of the Black, Latino and tribal communities — populations most affected by COVID-19

Both COVID-19 vaccines target and neutralize the virus’ spike protein — its “landing gear,” as Correy called it — which allows it to bind to a host cell. The vaccines show “astonishingly similar data,” and both are “quite well tolerated,” Correy said.

“This is marvelous, but I have to say we're not done,” he said during the webinar. “Vaccines don't save lives. Vaccinating people saves lives.”

The shipment, storage, handling and administration requirements associated with each vaccine make distribution a significant challenge, said panelist Jay Butler, MD, deputy director for infectious diseases at the Centers for Disease Control and Prevention. Butler also addressed the need for equity in allocation and distribution and discussed plans for prioritizing who receives a vaccine first

The biggest challenge, though, may be vaccine hesitancy on the part of the public. An October Gallup poll revealed that just 58% of Americans would get a COVID-19 vaccine. This is up from 50% in September, but still not high enough for the U.S. to achieve herd immunity.

“It's hard to overstate the apprehension and mistrust that is felt in some minority communities with respect to the vaccine and medical research generally,” said panelist James Hildreth, MD, PhD, president and CEO of Meharry Medical College in Nashville, Tennessee. “And paradoxically, the ones who need it the most are least likely to accept the vaccines.”

It helps that Pfizer and Moderna included minority populations in their trials, but more is needed to build public trust. Hildreth said partnering with trusted messengers, such as faith leaders and community organizers, will be key to encouraging vaccine uptake.

“In order for this to be successful, people have to stick out their arms and get injected with the vaccine,” he said. “And that's going to require an enormous effort across lots of different disciplines.”

Watch this webinar and others from the COVID-19 Conversations series — a partnership between APHA and the National Academy of Medicine — on demand at COVID19Conversations.org.