A project of the AAMC and CDC
aamc.org does not support this web browser.

What to Know About Preventing Respiratory Infections in the Months Ahead

Sept. 22, 2023
Young female doctor injecting vaccine in arm of senior man for immunization.

“It’s like practice before your big game,”  “You would never go out and play in the Super Bowl without having practiced for the season. This allows your body to have a little warm up” 

Jennifer Schuster, MD, MSCI director of the Pediatric Infectious Diseases fellowship program at Children’s Mercy and associate professor of pediatrics at the University of Missouri-Kansas City School of Medicine

Hospitals and health officials are bracing for a surge in viral illnesses in the coming months. However, this year, they are even more prepared to thwart them.

In addition to an updated flu vaccine available, an updated COVID-19 vaccine was just released , and doctors have new tools to prevent respiratory syncytial virus (RSV), which is common among children under age 2, as well as older adults. 

“We've got a lot of options to improve outcomes this year,” says Ross McKinney, MD, a pediatric infectious disease physician and the chief scientific officer at the AAMC. “Between the vaccines and some preventive treatments, things are looking pretty good.”

Here’s how things are stacking up against these common respiratory foes.


Every year, scientists make predictions on how the flu viruses from one year will mutate. This is in order to formulate an effective vaccine for the following year.

The vaccine looks like it's a good match with what's been circulating in the Southern Hemisphere,” says McKinney. “So I'm relatively optimistic about this one.”

Indeed, preliminary data from the 2023 Southern Hemisphere flu season show adjusted vaccine effectiveness of 52% against hospitalization and 55% against the dominant H1N1 strain.

Last year’s influenza vaccine was 54% effective in protecting people under 65, according to data from the Centers for Disease Control and Prevention. Around 40% to 60% is typical.

The annual vaccine, which includes four different flu strains, contains pieces of the virus that prompt the body to mount an immune response against the organism.

“It’s like practice before your big game,” says Jennifer Schuster, MD, MSCI, the director of the Pediatric Infectious Diseases fellowship program at Children’s Mercy and associate professor of pediatrics at the University of Missouri-Kansas City School of Medicine. “You would never go out and play in the Super Bowl without having practiced for the season. This allows your body to have a little warm up” in order to better fight the flu if you contract it.

The CDC recommends the flu shot for everyone six months and older; infants get some protection from their mothers’ vaccination during pregnancy. There are higher-dose options for people 65 and older and a nasal spray for people ages 2 to 49.

“Children under nine really need two doses of flu vaccine to be protected,” says Janet Englund, MD, professor of pediatric infectious diseases at Seattle Children’s Hospital and professor of pediatrics at the University of Washington School of Medicine. Since there was decreased uptake of the flu vaccine during the COVID-19 pandemic, she says, there are a greater number of children who need this extra protection.

When is a good time to roll up your sleeves? Now, says Englund.

“Some people are worried that they could get it too early, but this is not too early,” she says. That’s because flu is beginning to circulate, plus it takes two weeks for the shot to do its job.

Keep in mind that some people may run a fever or experience body aches afterwards and there can also be soreness at the site of the shot.


A common respiratory virus, RSV usually causes mild, cold-like symptoms, but can become dangerous if severe infection develops in babies 12 months and younger, particularly premature infants, as well as older adults and people with certain health vulnerabilities.

Doctors are hopeful that recently introduced tools, including vaccines and monoclonal antibodies for preventing RSV, will be effective ways to keep people well.

“These are products that we have never had before,” says Schuster. “Every pediatrician and family doctor will tell you that each winter, we see so many young infants [who] are hospitalized with RSV disease. To be able to change that and keep kids out of the hospital is a really big deal.”


Older people and those with compromised immunity will be the primary beneficiaries of RSV vaccines, says Zanthia Wiley, MD, associate professor of medicine in the division of infectious diseases at Emory University School of Medicine.

“These are older people with lung disease like COPD and asthma, diabetes, kidney disease, liver disorders,” she says. “Symptoms can progress to the point that people have lower lung infections and pneumonia. I would recommend the vaccine to them and anybody who is on dialysis or receiving chemotherapy.”  

The shot is approved for adults 60 and over and is available now, though insurance coverage will vary.

The CDC recommends that patients discuss with their doctors whether the benefits outweigh the risks, mainly side effects like redness and swelling at the injection site, fatigue, fever, headache, GI upset, and muscle or joint pain. A small number of people in the vaccine trials developed Guillain-Barré syndrome, a rare neurologic disorder, but it’s possible the cases occurred due to chance, the agency notes.

“The good news is the vaccine appears to last quite a while,” says McKinney. “So unlike flu and coronavirus vaccines, you don't need to give it right before you expect to be exposed. It has a pretty good duration.” McKinney says it is not yet clear whether this shot will be annual or needed less frequently.

An RSV vaccine has also been approved for pregnant women to provide immunity to their infants.

“The [Food and Drug Administration] has approved the vaccine for people who are between 32 to 36 weeks with the idea that the pregnant person would get the RSV vaccine, make the antibody, and pass it to their baby to protect them during that first period of life,” says Schuster.

Monoclonal antibodies

Infants are also eligible for new weapons in the respiratory infection toolkit: monoclonal antibodies, which are administered as a preventative measure.

Vaccines give you a little piece of the virus that can't make you sick, but stimulate your body to generate an immune response,” says Schuster. “Monoclonal antibodies just give you that immune response. They cut out the middleman.”

Nirsevimab is recommended for all infants who are younger than 8 months and born during — or entering — their first RSV season (usually fall through spring), the CDC says. It’s also recommended for children between the ages of 8 and 19 months with a heightened risk for severe RSV, such as those who are severely immunocompromised, and who are entering their second RSV season.

“It looks like this is pretty protective for the first six months of life, which is when we see the most severe disease in our infants,” says Schuster. “So, it’s an exciting development.”

Another monoclonal antibody, palivizumab, is available for children under 24 months with conditions that place them at high risk for severe RSV disease. It’s given once a month during RSV season.

Updated COVID-19 shots

Many people are eager to get the new COVID-19 vaccine, which is formulated to match the XBB variants — the predominantly circulating variant when the vaccines were developed a few months ago. Although new variants like EG.5 have since emerged, they are closely related to XBB, and the new COVID-19 vaccine should provide sufficient protection against severe disease and death from infection.

“We are seeing an increase in the EG.5, which is now the predominant variant, but all of these really fall under the Omicron variant,” says Schuster.

Like the original COVID-19 vaccine, the new shot is monovalent, containing just one viral strain.

“We expect to see good effectiveness in terms of the prevention of serious disease and a mild diminution of actual catching it,” says McKinney. “Primarily it makes infections milder and shorter.”

The updated shots contain part of the code from the virus’s spike protein, which induces the production of antibodies that recognize the virus when people subsequently get infected.

“They work exactly the same as the previous COVID vaccines that we're familiar with,” says Schuster. “However, the spike protein looks a little bit different because the spike protein in these new lineages looks a little bit different.”

The CDC recommends the shots for those 6 months and up. Insurance companies and Medicaid and Medicare are expected to cover the full cost of shot.

Priming the pump

Now that the new COVID-19 vaccine is available, Wiley says, people should feel free to get more than one vaccination at a time.

“If people see their primary care doctor within the next few weeks, they can elect to take their flu shot and their COVID vaccine at the same time or even all three vaccinations [flu, COVID-19, and RSV], if they are eligible for them” she says. “This is an especially good idea for people who cannot make it back to their doctor as regularly, such as someone who has transportation or mobility limitations.”

It makes sense to allow some time for any side effects to pass, says Wiley. Past reactions to vaccines — including fatigue, muscle aches, and headache — are a good predictor of what patients can expect.

“I tell people to get vaccines on a Friday so that they will have Saturday to be at home and rest,” she says.  

As good as the vaccines are, however, patients shouldn’t rely solely on them to keep themselves and others well, experts caution. They should also wash their hands frequently, steer clear of places where lots of people are gathered in close quarters, wear a high-quality mask, and stay home (if possible) when they’re sick.

“If you’ve got a respiratory virus,” says McKinney, “don’t spread the wealth.”