When COVID-19 vaccines first started rolling out in early 2021, the Centers for Disease Control and Prevention (CDC) advised people to wait at least two weeks before getting another immunization of any kind out of an "abundance of caution." But during the spring of 2021, they revised that guidance and now say the COVID-19 shot and other vaccines may be administered simultaneously.

Still, because vaccines for COVID-19 are relatively new, the CDC doesn't have a ton of data about how other vaccinations may affect it, or vice versa. As flu season draws closer and we remain in the pandemic, you may be wondering about the safety of getting both shots at the same time, and whether (or how) getting both could affect your immune immune response.

Here's what you need to know about getting the COVID-19 vaccine and the flu vaccine at or around the same time, according to infectious disease experts.

Is it OK to get the flu shot and COVID-19 vaccine at the same time?

According to Cassandra M. Pierre, MD, MPH, an infectious disease physician and medical director of public health programs at Boston Medical Center, yes. She tells Health that not only is it safe to get both shots at the same time, she actually recommends doubling up if you haven't had either vaccine yet or you're due for your second dose of the COVID-19 vaccine to help prevent the spread of both diseases in the community.

While people are just starting to get these two particular vaccines at the same time, getting multiple immunizations in one appointment isn't a new practice. For example, Gigi Gronvall, PhD, Senior Scholar at the Johns Hopkins Center for Health Security at the Bloomberg School of Public Health, tells Health that kids routinely get several shots-for example, the measles, mumps, and rubella (MMR) vaccines-at the same appointment. So introducing multiple viruses to the body at once doesn't impact how well your immune system can protect you from them. "Your immune system is capable of chewing gum and walking at the same time," Gronvall says.

In other words: it's unlikely your body would struggle to create an immune response to influenza because it was mounting one to COVID-19, or vice versa. According to the CDC, immunogenicity-the ability of a vaccine to promote an immune response-and adverse events are generally similar whether one shot or multiple shots are given. Dr. Pierre says the same principle applies to both COVID-19 doses and likely will apply when the CDC starts recommending COVID -19 booster shots, too.

Either way, it's not likely you'll feel significantly worse after getting both shots than you would had you just gotten one. Nicolas Barros, MD, an infectious disease specialist at Indiana University Health, tells Health he suggests using different limbs, if possible, to avoid having a localized pain reaction on the same limb from two vaccines. And while Gronvall says you may feel crummy, especially if you typically feel crummy after vaccines, getting two vaccines doesn't mean you should feel double the side effects.

"So far, with people who have gotten both, there are no significant changes in side effects," says Dr. Barros.

When should I get the flu and COVID vaccines?

In general, Dr. Pierre says doctors recommend getting a flu vaccine near the beginning of flu season, which usually occurs from September to May. Gronvall suggests getting the flu shot by the end of October. But because it's important as many people get the COVID-19 vaccine as possible, there's no problem with knocking both out at one appointment, and doing so as soon as possible. "Now is a fine time to go get a flu vaccine, especially if you can go get both of the vaccines," Dr. Pierre says. Just keep in mind special populations, like older people or immunocompromised individuals, may need a flu booster later on in the season, so talk to your doctor if you're concerned about the timing.

No matter when you go, try to get both shots if you haven't been vaccinated already. Last year, because most people were staying home more, wearing masks, and physically distancing in public, the US had very low numbers of influenza cases compared to previous years. Now, as a more transmissible variant of COVID-19 continues to surge and this year's flu season approaches, Dr. Pierre says it's ideal to seek protection against both. "We're really concerned about the resurfacing of influenza at a time when COVID-19 is rising," she says. "People are busy, so it's expedient to try to cut down on the number of appointments you have and just get both at once."

In the future, you may be able to get both the COVID-19 and influenza vaccines all in one shot; Dr. Pierre says several vaccine manufacturers are currently working on making co-vaccines. For now, though, you can get two jabs—ideally at the same appointment.