QCOSTARICA – The Comisión Nacional de Vacunación y Epidemiología (CNVE) – National Commission for Vaccination and Epidemiology – approved the application of the fourth dose against Covid-19 in people over 50 years of age or in people with risk factors or weakened immune systems.

The fourth dose can be applied four months after the third vaccine.
The Secretary of the CNVE, Roberto Arroba, explained that the fourth dose is not mandatory in any case.
Juan José Romero, epidemiologist at the National University (UNA), explained that it is a policy that is being taken globally.
Mid-April, the United States Food and Drug Administration (FDA) expanded its emergency-use authorization to allow adults 50 and older to get a second booster of the Pfizer or Moderna vaccine, reported the New York Times.
The NYT article explains one reason older adults may benefit from an additional booster shot is that the immune system tends to weaken as it ages and does not produce the same quantity or quality of antibodies as it did when it was younger.
On top of that, older adults often have other medical conditions that take up the body’s attention, putting them at higher risk of severe disease, said Dr. Christian Gaebler, an immunology researcher at Rockefeller University in New York City. “Diabetes, hypertension, obesity and chronic kidney disease are all risk factors for severe Covid,” he said. “And we know that these usually manifest in older age.”