The Health Ministry says headache, localized pain and a low-grade fever are the most common side effects reported after receiving a Covid-19 vaccine in Costa Rica.
Since December 24, the country’s National Pharmacovigilance Commission has received 3,536 “Events Supposedly Attributable to Vaccination and Immunization” (ESAVI) related to the Pfizer/BioNTech and AstraZeneca vaccines. This represents adverse events after 0.4% of the total vaccines administered as of the first week of May.
An ESAVI is defined as “any unfavorable, unintended health situation that occurs after vaccination/immunization but that does not necessarily have a causal relationship with the vaccination process or with the vaccine.”
Of the 3,536 ESAVIs, Costa Rican health authorities have identified 14 serious events, all of which occurred after receiving a Pfizer dose. These include four people with multiple comorbidities who died in the days or weeks after receiving the vaccine.
Those four deaths in detail:
- Two cases were determined as having a “conditional” tie to the vaccine. This means that while the factors that caused the death have not been firmly established, the vaccine is not known to have been a factor.
- Two cases were classified as “unlikely,” meaning they “do not meet the criteria to establish a causal relationship with the vaccine.”
Of the 10 remaining special-interest events, the Health Ministry detailed them as follows:
- Five events that were “probably” related to the vaccine.
- Two events that were “possibly” related to the vaccine, though the patient had other factors that may have caused it.
- Three “conditional” cases where pre-existing conditions are believed to have been a causing factor.
Costa Rica has administered more than 1.46 million doses of the Pfizer and AstraZeneca vaccines. More than 3,900 people in Costa Rica have died related to Covid-19, and 529 people are in intensive care with Covid-19 as of Wednesday afternoon.