According to data from the European adverse reaction surveillance platform, 163,582 suspected side effects of AstraZeneca's vaccine (Vaxzevria), 106,375 from Pfizer, 14,235 from Moderna and 202 from Janssen had been reported by 13 April.

In Portugal, the majority of suspected side effect cases reported are related to Pfizer's vaccine, with 3,220 situations. There were 730 suspected adverse reactions to AstraZeneca's vaccine and 241 to Moderna's.

Suspected adverse reactions are clinical manifestations that may or may not be related to the vaccine, but which appeared after administration.

According to the European Adverse Reaction Surveillance Platform, the data indicate that most of the recorded reactions are classified as "general and related to the administration site", followed by nervous system, musculoskeletal and gastrointestinal reactions.

On 14 April, the Community executive disclosed that the European Union (EU) has reached 100 million doses of vaccine administered against Covid-19 by European countries, out of a total of more than 126 million doses received.

The announcement came a day after US health authorities recommended "a pause" in the administration of Janssen's (owned by Johnson & Johnson) vaccine to allow investigation of reports of blood clots potentially associated with the administration of the drug.

After that, the pharmaceutical company Johnson & Johnson itself took the decision to delay the distribution of its vaccine in Europe.

Despite this, Portugal received on 13 April the first 31,200 doses of Janssen's Covid-19 vaccine, which will be stored until there is a decision from the European regulator on its use.

AstraZeneca's vaccine was the first to be embroiled in controversy because of suspected side effects related to clot formation, and was even suspended in a number of countries, such as Portugal, and then resumed.

However, in relation to AstraZeneca's vaccine, the Directorate-General of Health (DGS) now recommends administration only to people over 60. For people below this age who have already taken the first dose, the Technical Commission on Vaccination against Covid-19 has already admitted that the second dose can be of any other brand.