Will they arrive in time to combat the surge?

and This summer, the number of new coronavirus infections has increased sharply. The planned introduction of an improved vaccine in the autumn raises an important question: Will the vaccine arrive in time to be effective?

The coronavirus pandemic has not followed a predictable seasonal pattern like influenza, which typically begins spreading in the fall and peaks in late winter and spring. Flu vaccinations, which take two weeks to become fully protective, are typically recommended in September or October.

A new coronavirus vaccine targeting the KP.2 strain, a descendant of the highly contagious JN.1 variant that emerged last winter, is due to be distributed in the coming weeks.

Even if a vaccine becomes available within the next month, immunologists and infectious disease experts don't expect it to have much effect on the current summer surge, but vaccinations will be important as the U.S. heads into fall and winter, a time when cases could rise again.

“History suggests that if we were to see a new big wave of COVID, it would more likely come in the fall than it would this time of year,” said John Moore, a professor of microbiology and immunology at Weill Cornell Medical College. “In hindsight, we could have done it sooner. The current plan is very hard to criticize because it's logical and rational.”

“The more you do it, or even if you don't, you're going to be criticized either way,” he added.

COVID-19 outbreak likely to surge throughout the yearAccording to the Centers for Disease Control and Prevention (CDC), the number of COVID-19 cases has more than doubled since 2024 compared to 2025. COVID-19 data from the past four years shows peaks in the winter months (December and January) and hot summer months (July and August). According to the CDC's wastewater data tracker, in 2024, the number of cases began to increase in June and remains high.

Despite the two outbreaks, the Food and Drug Administration is following a process similar to that used to update the annual flu shot, with vaccine experts selecting COVID-19 strains in the spring for vaccination campaigns in the fall.

Akiko Iwasaki, an immunologist at Yale University, said ideally, public health officials would aim to administer coronavirus vaccines just before each wave to reduce infections and severe illness.

But until the U.S. decides on a timing for vaccinations, “two booster doses per year, one in early summer and one in the fall, is probably the right answer right now,” she said, adding that the timing of vaccinations starting in the fall is “a good problem to have, but a difficult one.”

“Of course, these booster shots have to be well-matched to the variants that are circulating,” she said.

In fact, in February The FDA and CDC recommend a booster shot. Vaccinations have begun targeting people at highest risk of the most severe complications from COVID-19, primarily those over 65, to provide a safeguard against a possible second summer surge in infections — a surge that would have occurred anyway, as only about 10% of adults over 65 had received both doses of the 2023-24 booster vaccine.

Last fall, CDC data Increase in hospitalizationssome doctors Criticized FDA Because they waited too long to introduce an improved COVID-19 vaccine.

Is the FDA considering changing the fall vaccine rollout timeline, which is currently early September?

In an email, an FDA spokesperson directed NBC News to comments made by CDC epidemiologist Ruth Link-Gelles at an FDA advisory committee meeting in June, in which she highlighted the difficulty of determining the best time to administer a COVID-19 vaccine.

“For influenza and RSV, we have years of data showing very similar trends over time,” she says, “so while we can't predict exactly when those seasons will start, we can get pretty close. That's not the case at all with COVID-19. We've seen spikes in cases in the summer, in August for the last few years, so timing the COVID-19 vaccine rollout is going to be a bit of a game.”

Dr. Isaac Bogoch, an infectious disease specialist at the University of Toronto, said most people, including healthy younger people, probably won't need more than one dose of the COVID-19 vaccine a year.

“I think it's impossible to make blanket statements about a population of more than 300 million people,” he said. “Some people who are at risk of severe illness may have had a long period of time between now and their most recent vaccination, which may put them at greater risk. In those circumstances, it might be a reasonable idea to get vaccinated before the autumn campaign.”

How long people are protected from COVID-19 after infection depends on a number of factors, including the severity of the infection, the strain of the virus, and the age and health of the infected person. Studies have shown that protection may last for three months or more.

Dr. Ofer Levy, director of the Precision Vaccine Program at Boston Children's Hospital, warned against a false sense of security for people who were infected during the summer surge.

Even if people are infected, Levy said the vaccine is still important because natural infection doesn't provide the same level of protection.

“Does natural infection confer some protection? Yes, I think it does,” Levy said, “but it's not the same level of protection that you get from a vaccine.”

Weill Cornell's Moore said the FDA is right to stick to its fall timeline.

“I don't want to downplay what's going on right now, but if we're going to see a bigger surge, it's going to be later this year,” Moore said.