Several major pharmaceutical companies, including Pfizer, AstraZeneca, Moderna, and Johnson & Johnson, developed and proposed Covid-19 vaccines in an exceptionally short period. This unprecedented speed raised many questions and sparked public concern.

After millions of doses were administered and nearly five years of observation, medical experts have identified a number of confirmed adverse effects. These include high blood pressure, cases of myocarditis and pericarditis, allergic reactions, and reports of heavy menstrual bleeding.

The question of whether vaccines can cause serious side effects remains controversial. While many people, including some scientists, reject a direct link between Covid-19 vaccines and certain illnesses, recent research has reopened the debate.

A study published a few months ago suggested that Covid-19 vaccines may, in rare cases, be associated with serious adverse effects. This publication has intensified discussions within both scientific and public circles.

The research was carried out by the Global Vaccine Data Network and analyzed data from more than 99 million individuals. Eight countries took part in the study: Argentina, Australia, Canada, France, Denmark, Finland, New Zealand, and Scotland.

According to the researchers, most vaccinated individuals were between 20 and 59 years old. France recorded the highest number of administered doses among the participating countries.

The vaccines examined in the study were produced by Pfizer, Moderna, and AstraZeneca. The findings failed to provide reassurance to healthcare professionals and raised additional concerns among patients.