When to get your shots

The consensus among experts is that if you only have the time or inclination to make a single vaccine appointment, it's safe to get your COVID-19, flu, and RSV shots together, if you're eligible.

However, if you're able and inclined to get your shots separately and time them throughout the fall, that may have some benefits. Arnold Monto, co-director of the Michigan Center for Respiratory Virus Research and Response and a professor emeritus of epidemiology at the University of Michigan, said he prefers timing his vaccines to when he'll get the most out of each one, but added that "it's better to get both together than not to get one or the other."

COVID-19 vaccines

COVID-19 vaccines provide fairly durable protection against hospitalization, however, the immunity provided against getting the disease at all is more short-lived, STAT reports. What's more, COVID-19 has not shown to follow a seasonal pattern, and while launching COVID-19 shots in September alongside flu shots may be beneficial from a delivery perspective, it may not provide the best protection, experts said.

"I think it's complicated in general right now because influenza and SARS-CoV-2 behave differently," said Florian Krammer, an influenza virologist at Mount Sinai's Icahn School of Medicine.

Katelyn Jetelina, an infectious disease epidemiologist, said she tries to time her COVID-19 shots to avoid getting sick at all, rather than just avoiding a severe case of the disease.

"I know that with the vaccines, the primary purpose is [to prevent] severe disease. But I'm using them for their secondary purpose, to help reduce disruptions in my life, even if that's imperfect and short term," she said. "And so I'm thinking of it like: Might as well wait for that winter wave, which will coincide … with fun holiday activities that I don't want to miss."

Jetelina said she plans on getting a COVID-19 and flu shot together around Halloween.

However, a number of experts said getting a COVID-19 shot now, as long as you haven't recently had COVID-19 or another dose of a vaccine, makes sense.

"Right now there's a lot of SARS-CoV-2 cases and so if people didn't have SARS-CoV-2 in a while, it might be good to get a vaccine relatively quickly … because that reduces your chances of getting infected or getting symptomatic disease in the near future," Krammer said.

However, Krammer noted the concern that doing so might leave a person less protected in the winter is "valid."

"It's hard to weigh the risks and say: 'Okay, it would be better to take a risk now and be better protected later versus better protected now, and maybe less well protected later,'" he said. "I think to make these calculations … in a quantitative way, that would be really hard."

Flu vaccines

If you're willing to get your COVID-19 and flu shots at different times, waiting for your flu shot could make sense. CDC recommends people get their flu shots by the end of October.

"You really want to think about getting your appointment or making your plan to get vaccinated sometime around the last half of September through the end of October," said Judith O'Donnell, chief of infectious diseases at Penn Presbyterian Medical Center.

The flu is more seasonally predictable than COVID-19. Flu is typically a winter illness, with cases often peaking between late December and mid-to-late February.

Similar to COVID-19 vaccines, flu shots are better at preventing severe disease than preventing infection entirely, and the immunity provided by the vaccines decline over time.

"What we need to communicate is that these vaccines will keep you from severe illness and death. And they do very well for that," said Kanta Subbarao, a professor of microbiology at Laval University.

"What I think that the public wants, and is fed up with vaccines because they think they're not getting, is protection from infection. And that is true for flu vaccines. It's true for the Covid vaccines," Subbarao said. "So the messaging has to be that you take these vaccines to keep yourself from getting severely ill — ill enough to require hospitalization, or to have complications, and so on."

Subbarao said she will get a COVID-19 shot as soon as she can, but plans on waiting to get a flu shot.

"What I want is protection from November to March. And I think we get six months of protection from flu [shots]," she said. "And so if I want to be protected from November to March, then what I would say is that I think I could get vaccinated in late September or October."

Michael Osterholm, director of the University of Minnesota's Center for Infectious Disease Research and Policy, recommended holding off on your flu shot until the flu is circulating where you live.

"I urge people to wait until we start seeing flu activity in the community and not just sporadic cases but sustained transmission," he said. "I realize that's a challenge to get scheduled at that point. But at the same time, you don't want to lose the protection you have from the vaccine in its earliest days after administration compared to what may be a 20% to 50% reduction over the winter season from the time you got the vaccine."

Young children, however, will need an initial course of two doses to best protect from the flu. Alicia Budd, team lead of the influenza division at CDC's National Center for Immunization and Respiratory Diseases, said any children who need two doses can get their first shot now.

RSV vaccines

Aside from pregnant people, RSV vaccines are only available for older adults. Two of the three available vaccines — Pfizer's Abrysvo and Moderna's mResvia — are available for people ages 60 and older. Meanwhile, GSK's Arexvy is available for people ages 60 and older and those ages 50 to 59 who are at high risk of serious disease.

Given these vaccines are newer, it's not yet known how often people will need additional doses. However, it's clear that the GSK and Pfizer vaccines don't require annual vaccination, meaning any older adult who's already received an RSV shot isn't eligible for another one.

In a meeting in June, CDC's Advisory Committee on Immunization Practices (ACIP) changed its recommendation on who should get an RSV shot. Previously the policy recommended people ages 60 and older get a shot if they and their doctors agree it's needed. However, doctors argued the approach was too confusing and time-consuming, so ACIP made an adjustment, saying that people 75 and older should get the RSV shot if they haven't yet, as should people ages 60 to 74 who have health conditions increasing their risk of serious illness.

Meanwhile, pregnant people are able to get Pfizer's RSV shot, and CDC recommends pregnant people who will give birth during RSV season, which lasts from September to January in most parts of the United States, receive their shot between week 32 and 36 of each pregnancy. (Branswell, STAT, 9/4; Schmall, New York Times, 9/4; Bendix, NBC News, 9/5)

In March 2020, the  World Health Organization declared COVID-19 a global pandemic. Here's what we've learned about the virus since then, what we still don't know, and its ongoing impact on both people's health and society at large.