If you’re hoping to make just one trip to the doctor’s office or pharmacy for your flu and Covid shots this fall, here’s some good news: A new study found that getting both vaccines at the same time does not increase the risk of serious side effects. This scheduling is consistent with current CDC guidelines, which do not advise a waiting period between the vaccines. For the first several months after Covid vaccines became available, the CDC recommended waiting two weeks before or after receiving one to get other vaccines, including the flu shot.
The study covered the flu vaccines that were available between September 2022 and August 2025. (Manufacturer information on co-administration of the Covid vaccine with the newly approved Moderna mRNA flu vaccine isn’t yet available.)
Published in the Annals of Internal Medicine in June, the study was a target trial emulation—a research design that mimics a randomized clinical trial using real-world data. It compared around 700,000 medical records from people who had received Covid and seasonal flu vaccines with 1.8 million records from those who had received only flu vaccines.
The study included participants (average age, 69 years), many of whom had preexisting conditions and regularly took multiple prescription medications, including blood thinners, diabetes drugs, corticosteroids, and immunosuppressants. More than half got the high-dose flu vaccine recommended for adults ages 65 and older.
Of the 46 specific adverse events that the researchers tracked over a 90-day period—including heart issues, blood clots, neurological issues, and autoimmune conditions—no significant differences were seen between those who had received a flu vaccine alone and those who had received both vaccines on the same day, one after the other.
The study excluded people receiving end-of-life care, those recently diagnosed with Covid, and anyone who had visited the emergency department or been hospitalized in the week before vaccination.
Much has changed since the early days of Covid. The virus itself has evolved, and vaccines have been updated to address new variants. At the same time, most people have been vaccinated against Covid or have had Covid, and because of this, they may be less likely to experience adverse effects from the vaccines, the study’s authors suggest.
The study had limitations. Most of the participants were male, white, or older, which may limit how well the findings apply to other populations. And since the study was not an actual randomized clinical trial, there may have been unmeasured variables that affected the outcomes.
The takeaway. If you’re due for your next Covid vaccine, it’s safe—and more convenient—to get it at the same time as your annual flu shot. From a public health perspective, giving them both at the same visit could make it easier for more people to stay up to date with these important vaccines, thereby reducing the spread of these illnesses.
