³Ô¹ÏÍøÕ¾

The Food and Drug Administration approved and granted emergency use authorization on Aug. 22, 2024, for the newest, . The Centers for Disease Control and Prevention quickly to protect against severe illness.

The is a good reminder of why people need to stay up to date with their vaccines.

As the fall and winter seasons approach, the usual seasonal respiratory viruses, including , will also be on the rise. Vaccines are now available to help protect against these viruses.

The Conversation asked to explain why officials recommend that people get these shots over the coming months.

What strain is the new COVID-19 shot based on and why?

The COVID-19 vaccine has been updated several times since the original shot in 2020-21 to keep up with how the SARS-CoV-2 virus is changing.

In September 2023, the CDC recommended that all people get the newly updated vaccine that , the variant that had been dominant in the U.S. that summer, regardless of whether they had received all recommended shots in the past.

Now, in August 2024, the XBB.1.5 variant is no longer around and has been replaced by the , which make up .

Moderna and Pfizer both made updated formulations of the COVID-19 shot that target this new KP.2 variant. It is a monovalent vaccine, which means it includes only the KP.2 strain.

This strain was selected because it was the most common variant at the time the choice was made. Even when new variants such as KP.3 emerge, we researchers expect the updated vaccine to protect against the newer strains. For example, the 2023-24 vaccine was designed to target the XBB.1.5 strain, and studies showed that it that later emerged.

The CDC recommends a for everyone 6 months and older, with some exceptions. Children 6 months to 4 years old who have not received any prior shots of COVID-19 vaccine still need two or three shots of the updated 2024-25 vaccine. Adults 65 and older and children and adults with certain health conditions may require an as well.

People who recently had a SARS-CoV-2 infection may consider for three months after the illness, since risk of reinfection is thought to be low during the months after infection.

How did the 2023 updated vaccine perform?

Recent studies have shown that people who received the 2023-24 vaccine were 54% less likely to develop , 39% to 51% less likely to , and 50% to 53% less likely to be compared with unvaccinated people.

The vaccine was most effective among those who had received their shot more recently.

What is the best timing for the shots?

COVID-19 and have been rising since May 2024, with the highest rates seen in adults 65 and older and infants under 6 months old. Therefore, public health experts are recommending that people get the COVID-19 shot as soon as possible to protect against severe illness.

Because infants younger than 6 months are not old enough to be directly vaccinated, COVID-19 vaccination during pregnancy is the .

When it comes to the flu, and seem to rise steeply between November and December. Some years, however, such as the , they start as early as October.

It’s important to remember that vaccines do not offer immediate protection. You need about two weeks for your body to generate enough antibodies to offer protection. is a good time to get the flu shot to ensure you are protected in time. However, if you aren’t able to get the shot before November, it’s important to know that it is still helpful to get the shot as long as flu is around.

Is it OK to get both the COVID-19 and flu shots at the same time?

Getting the COVID-19 and flu shots together can certainly make it easier to get up to date with these recommended vaccinations. Data shows that getting the and .

Some vaccine companies are working to to reduce the number of shots needed. This vaccine still needs to be approved by the Food and Drug Administration but could become available soon.

Who should get the RSV shot and when?

is another common respiratory virus that can cause severe illness in young children and older adults. There are two groups of people who should get one of the three currently available RSV vaccines: adults 60 years and older and pregnant people. The of either GSK’s AREXVY, Moderna’s mRESVIA or Pfizer’s ABRYSVO for all adults 75 years and older and adults between the ages of 60 to 74 who are at increased risk of severe RSV disease.

Unlike the COVID-19 and flu shots, additional RSV doses are not currently recommended, because research suggests that the vaccine offers protection for . These vaccines are relatively new, however, and more data will be needed to see how long this protection really lasts. Additional doses may be recommended in the future.

The CDC recommends only Pfizer’s shot for people in weeks 32 to 36 of pregnancy between September and January. The Pfizer vaccine is the only RSV vaccine that has been for use in pregnancy.

These vaccines are different from the antibodies that can be given to infants at or after birth, called Beyfortus (nirsevimab). The CDC recommends for infants who are younger than 8 months old born during or shortly before their first RSV season. For some children who are 8 to 19 months old and are at increased risk of severe RSV disease, a dose of nirsevimab may also be recommended during their second RSV season.

Both the offer safe and effective options for preventing RSV in young babies.

Pregnant people should get advice from their health care professionals about which option is best for them.

Annette Regan receives funding from the ³Ô¹ÏÍøÕ¾ Institutes for Health and the US Centers for Disease Control and Prevention. She has served on a Data Safety Monitoring Board for Moderna Inc.