New Side Effect of Vaccines Under Study

The Spanish Agency for Medicines and Health Products (Aemps) has begun to study a new side effect of Pfizer and Moderna vaccines. Specifically, the effect would be related to the risk of menstrual disorders after dose administration. The research also focuses on pregnant and lactating women, as well as children after receiving the booster injection, according to the 13th Pharmacovigilance Report.

Until February 6, Spain has registered 400 deaths and around 60,000 notifications of adverse effects after receiving a dose of the vaccine. As more than 97 million doses have been administered, this would mean that there are 62 notifications of these events for every 100,000 injections. Of these, less than 12,000 were considered serious.

changes in menstruation

However, from the Aemps they stress that these effects “does not mean they are related to vaccination“. In addition, the most frequent are fevers, pain in the vaccination area, headaches, dizziness, myalgias and arthralgias, and in 74% of cases occur in women. As for Pfizer, no new adverse events have been reported, but possible menstrual disorders after injection are being studied, as is Moderna.

This is because two recent studies argue that there is an increase in the frequency of these disorders after injection, with “mild and transient” changes in menstrual cycles. With regard to their use in pregnant and lactating women, the EMA does recommend the use of Pfizer and Moderna as they did not observe “negative effects” during the second and third trimesters of pregnancy. “Although the information available on vaccination during the first trimester of pregnancy is more limited, no new information on increased risk of miscarriage“Aemps explains.

Fewer adverse effects in booster doses

There is no big difference between Pfizer and Moderna. As of February 6, 62,903,742 doses had been administered from the first and 33,253 reported, while 22,357,090 doses had been administered from the second and 11,779 adverse effects were recorded. So, In both vaccines, notifications account for only 0.053% of the total number of injected doses..

A little more serious effects are observed in Pfizer, with 6,746 cases (0.011%), than in Moderna, with 1,807 (0.008%), although it is not significant. Regarding the children, of the nearly 1.8 million doses administered, only 132 (0.07%) had adverse effects after being vaccinated, 48 of them considered serious.

Finally, with booster doses notifications have plummeted. Of the 22,307,885 administered (44% by Pfizer and 56% by Moderna), only 785 (0.003%) cases of adverse effects have been recorded. Of these, 36% belong to those vaccinated with Pfizer and the rest, to those immunized with Moderna. Again, the majority of cases (69%) occurred in women. With these booster injections, the Aemps has reported that there is a “higher proportion” of lymphadenopathy or lymph node disease.

–