What do we know about the AstraZeneca vaccine and blood clots?

Dr Khan examines what we know about the suspected link between the vaccine and blood clots and relates his experience of vaccinating people in his community on a vaccination bus.

The team at Oxford-AstraZeneca must be tearing their hair out after yet another week of hitting the headlines over a possible link between the vaccine and rare blood clots. Back in March, the European Medicines Agency (EMA) said it had found no link between the vaccine and an “overall risk” of blood clots. The agency could not completely rule it out, however, and asked governments to “raise awareness” about blood clots and include information about them for healthcare workers and people who were being vaccinated. Later, the agency said these rare blood clots should be listed as potential “rare side effects” of the vaccine. Since then, the UK’s Medicines and Healthcare Products Regulatory Agency (MHRA) has taken precautionary steps and advised anyone with potential symptoms of a blood clot four days or more after getting the vaccine to seek urgent medical advice while it investigated claims of a link with the vaccine further. On April 7, it stated that: “It is preferable for people under the age of 30 with no underlying health conditions to be offered an alternative vaccine where possible once they are eligible.” This is because while the benefits of having the vaccine vastly outweigh the risks for those in higher age groups, the balancing act becomes trickier for those statistically less at risk of being hospitalised by COVID-19. The agency was careful to point out that there is still no conclusive evidence that the vaccine causes clots, but that the links were getting “firmer”.