What are the possible side effects of Covid vaccines?
All medicines, including vaccines, have some side effects. The most common with Covid punctures are mild and short-lived, including localized pain, fatigue, or aches and pains.
However, the Oxford / AstraZeneca puncture has been linked to a small but worrying number of reports of blood clots combined with low platelet counts (platelets are fragments of cells in our blood that help it to clot).
These include a rare clot in the brain called cerebral venous sinus thrombosis (CVST). In an unvaccinated population, the highest estimates suggest that there may be 15 to 16 cases per million people per year. But the combination of CVST or other rare clots with low platelets and sometimes unusual antibodies is also very rare, and that combination is at the center of current concerns.
The Medicines and Healthcare Products Regulatory Agency (MHRA) said recipients of the Oxford / AstraZeneca injection should be on the lookout for new headaches, blurred vision, confusion or seizures that occur four days or more after vaccination.
The MHRA also noted shortness of breath, chest pain, abdominal pain, leg swelling and unusual bruising on the skin as reasons to seek medical advice.
How many cases have there been?
As of March 31, the MHRA said it received 79 case reports of blood clots combined with low platelets, including 19 deaths, following more than 20 million doses of the Oxford / AstraZeneca injection. That equates to about four cases for every million people vaccinated.
The MHRA says that blood clots combined with low platelets can occur naturally in unvaccinated people, as well as those who have contracted Covid, and that while the evidence for a link to the Oxford / AstraZeneca vaccine has become stronger, more research is needed.
How can the vaccine cause these problems?
At present, the mechanism by which the puncture could cause clotting problems remains unclear. But experts have noted a similarity to a clotting event that is sometimes seen among people receiving the anticoagulant drug heparin, whereby antibodies are generated that cause platelets to activate.
What is the current official recommendation?
The MHRA, along with the EMA and the World Health Organization (WHO), have repeatedly said that people should continue to take the Oxford / AstraZeneca injection because its benefits in preventing Covid infection far outweigh any risks.
The UK’s Joint Committee on Vaccination and Immunization (JCVI) said it was recommending that people aged 18-29 be offered other Covid vaccines, if available, provided they are healthy and have a low risk of Covid.
Pregnant women should discuss with their doctors whether they should undergo the Oxford / AstraZeneca injection, as pregnancy can increase the risk of blood clots, the MHRA said.
Does the birth control pill increase women’s risk of blood clots more than the Oxford / AstraZeneca injection?
Combined hormonal contraceptives, which contain estrogen, have been associated with an increased risk of blood clots, including CVST, deep vein thrombosis, and pulmonary embolism.
According to a 2014 EMA review, the risk of blood clots ranged from five to 12 cases per 10,000 women taking combined hormonal contraceptives for one year, compared to two cases per year per 10,000 women not using such contraceptives. .
Should I get a second dose of the Oxford / AstraZeneca jab?
The vast majority of people who received a first dose of the jab, including those under the age of 30, should receive their second dose, with a few exceptions.
“Anyone who has experienced brain or other blood clots with low platelet levels after their first dose of Covid-19 Vaccine AstraZeneca vaccine should not receive their second dose,” the MHRA said. “Anyone who has not had these side effects should show up for their second dose when invited.”
Nicola Davis Science correspondent and Jon henley Correspondent in Europe
George is Digismak’s reported cum editor with 13 years of experience in Journalism