Milestones :: Perspectives :: Research
Statement of the COVID-19 subcommittee of the WHO Global Advisory Committee on Vaccine Safety (GACVS) on safety signals related to the Johnson & Johnson/Janssen COVID-19 vaccine
19 May 2021 Statement
….The GACVS COVID-19 subcommittee met virtually on 11 May 2021 to review available information and data on thromboembolic events (blood clots) and thrombocytopenia (low platelets) after vaccination with the adenoviral vectored J&J vaccine. This condition is referred to as thrombosis with thrombocytopenia syndrome (TTS). Current evidence suggests a plausible causal association between the J&J COVID-19 vaccine and TTS. Clinically, the features of TTS following vaccination with this vaccine appear similar to those observed following another adenoviral vectored vaccine, the AstraZeneca COVID-19 vaccine. TTS does not appear to be associated with the mRNA COVID-19 vaccines. The exact mechanism by which this rare condition occurs is not fully understood. (1) To date, the only possible risks factors identified are age and gender (with more cases reported in women).
The subcommittee reviewed detailed surveillance data from the United States, which included stimulated passive surveillance and a small active surveillance cohort.
Based on a careful scientific review of the available information, the subcommittee came to the following conclusions and recommendations [nine recommendations at title link above]:
– The benefits of the J&J COVID-19 vaccine continue to outweigh the risks of TTS. As the only single dose COVID-19 vaccine approved for use to date, the vaccine may be an important tool for accessing difficult-to-reach populations, thus playing a key role in preventing infections and reducing deaths across the world…
…The GACVS COVID-19 subcommittee will continue to review the safety data from all COVID-19 vaccines and update any advice as necessary. Open, transparent, and evidence-based communication about the potential benefits and risks to recipients and the community is essential to maintain trust. WHO is carefully monitoring the rollout of all COVID-19 vaccines and will continue to work closely with countries to manage potential risks, and to use science and data to drive the response and update recommendations…