Vaccine opponents resurface misleading claims about study linking flu vaccine to potential stroke risk

Social media posts in both English and Spanish resurfaced misleading claims about a study linking the flu vaccine with potential stroke risk and casting doubt on the vaccine’s safety. One user inaccurately claimed that older adults who received the flu vaccine had a stroke 42 days after being vaccinated. 


These claims began circulating in October 2023, when an FDA preprint study was released. They present a narrative that flu vaccines are unsafe, which may promote distrust in public health guidance. Ensuring that FAQ pages and informational materials include information about flu vaccine safety and benefits is recommended. While the study mentioned in these posts found a slight increase in stroke risk in older adults who got a bivalent COVID-19 vaccine at the same time as the high-dose flu vaccine, a similar increased risk was also seen in people who only got the flu shot, indicating that the flu shot is the most likely source of the elevated risk. Messaging may emphasize that experts still recommend getting both vaccines because the benefits continue to outweigh the risks.