- The European regulator this week declared the AstraZeneca-Oxford University vaccine safe.
- But it will keep investigating reports of rare clots after vaccination, particularly among younger women.
- These investigations into side effects shouldn't worry us - they're a sign monitoring is working.
All effective medicines have side effects. We put up with them because, overall, the medicines make us feel better, or prevent something far worse.
The same principle applies to COVID-19 vaccines.
The benefits of
The European Medicines Agency (EMA) said it found no increased risk of
The EMA still recommended that people in this demographic take the shot because the risk of these blood disorders was "extremely small."
Despite the recommendation, France announced Friday that it would not give people under 55 AstraZeneca's vaccine.
Meanwhile, a large trial of more than 32,000 people in the US, Chile and Peru found that AstraZeneca's vaccine was 79% effective at preventing COVID-19 with symptoms, and 100% effective at protecting against severe illness and hospitalization, AstraZeneca announced Monday.
There were no reports of blood clots, including blood clots in the brain, in this trial.
Ian Douglas, professor of pharmacoepidemiology at the London School of Hygiene and Tropical Medicine, told Insider that the EMA's continued investigation was not worrying, but "reassuring."
It not only showed that potential side effects were being monitored closely, but that regulators were being upfront with the public, he said.
"For these reports to happen, there needs to be a suspicion of a link. But everytime we hear it, it won't mean that it has been caused by the vaccine necessarily," he said.
"It would be worse if all this was being done in secret, and something got out."
Lots we still don't know about the rare blood clots
There are lots of details that we don't yet know about the 25 reported cases of serious blood clotting problems: 18 clots in the brain, seven with DIC.
It's possible that these people were at increased risk of blood clots anyway. For example, they may have had underlying illnesses linked to clots, including COVID-19, or an inherited blood disorder. Smoking, the combined oral contraceptive pill, and hormone replacement therapy are all common reasons a woman under 55 may have an increased blood-clot risk.
The EMA also said that a greater number of women under 55 may have been immunized with AstraZeneca's vaccine, due to targeted vaccine campaigns in different EU countries.
The EMA has updated the AstraZeneca vaccine's leaflet for patients and
Regulators may well establish more potential links between serious illness and other COVID-19 vaccines over the next few months, and issue more guidance. This shouldn't cause alarm: it's simply a sign that the monitoring system works.