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HomeCovid 19 UpdatesSerious Covid vaccine side effects still rare in Costa Rica: Health Ministry

Serious Covid vaccine side effects still rare in Costa Rica: Health Ministry

The Health Ministry says headache, localized pain, muscle aches 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 7,148 “Events Supposedly Attributable to Vaccination and Immunization” (ESAVI) related to the Pfizer/BioNTech and AstraZeneca vaccines. This represents adverse events after 0.2% of the total vaccines administered through July 30.

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 ESAVIs, Costa Rican health authorities report 36 serious events. These include 13 people who died in the days or weeks after receiving the vaccine.

All 13 of those deaths have been analyzed by Costa Rican authorities. The Health Ministry details them as follows:

  • Three 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.
  • Eight cases were classified as “unlikely,” meaning they “do not meet the criteria to establish a causal relationship with the vaccine.” 
  • Two cases were classified as “possible,” meaning the vaccine or “other factors of the patient” may have contributed to the event.

Of the remaining serious events, the Health Ministry detailed them as follows:

  • Thirteen “probable” events, given the potential relationship between the symptom and the administration of the vaccine.
  • Six “possible” cases, since the symptoms may be due to other preexisting factors.
  • Four “conditional” cases, meaning pathologies presented by the patient could have triggered the condition.

Individuals can report adverse events that may be attributed to a Covid-19 vaccine to the health center at which they received the shot, or at

Costa Rica has administered 4.28 million doses of the Pfizer and AstraZeneca vaccines. The shots are helping to reduce Covid-19 mortality, the Health Ministry says.

More than 5,500 people in Costa Rica have died related to Covid-19, and 453 people are in intensive care with Covid-19 as of last Friday.

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