On Nov. 6, 2024, data from the VENUS (Vaccine Effectiveness, Networking, and Universal Safety) study in Japan revealed that the risk of developing long COVID is significantly lower when people have been recently vaccinated before infection.

The retrospective study followed participants diagnosed with COVID-19 between August 2020 and December 2022. The incidences of 36 post-COVID-19 conditions were monitored 3, 5, and 8 months after infection. Of the 84,464 participants, 9,642 (11.4%) developed post-COVID-19 conditions over 8 months.

In total, 84,464 participants were assigned one of three vaccination status groups (distant, intermediate, or recent vaccination), with distant vaccination occurring 365 days or more prior to infection, intermediate being 150 to 364 days after their last vaccine dose, and recent meaning receiving the vaccine 14 to 149 days before infection.

The study showed that the distant vaccination group had a higher risk for most of the 36 long-COVID symptoms compared to the most recent group, especially for respiratory conditions and heart conditions. Overall, the risk of developing 28 out of 36 long-COVID symptoms lessened when vaccines were effective, or up to 5 months after the last dose, the authors reported. The study was published n Vaccine.