The National Health Surveillance Agency (Anvisa) said in a statement today (23) that there is still not enough evidence to recommend the use of a third dose as a boost to the two doses already taken against covid-19 in most immunizers, with the exception of single dose, like Janssen’s.
Discussion and studies on the third dose began, especially in light of the emergence and circulation of variants of the new coronavirus. In its report, Anvisa says that it is not known for how long the protection given by the two doses (or single dose) will last and whether there will be a need for booster doses at intervals.
Anvisa recalled that there is a discussion within the international community of health authorities that ponders the fact of thinking about a third dose when most of the world is far from immunizing the total population over 18 years old.
“Experts and institutions like the World Health Organization say that public health policy makers need to look at the bigger picture when they are considering the possibility of providing booster doses, including the fact that many vulnerable people and health professionals can not having received even the first dose of a vaccine against covid-19”, explains the Agency.
The agency said it will assess if and when a third dose will be needed. The agency added that it follows studies on the emergence of new variants and impacts on vaccines.
“So far, all vaccines authorized in the country maintain protection against serious illness and death, according to published data. There are still no data or conclusive studies that indicate the need for a booster dose of authorized vaccines”, says the note from the health authority.
So far, three clinical studies on the necessity and convenience of the third dose have been approved, one by Pfizer/BioNTech and two by AstraZeneca.
+ Learn about the effectiveness of each vaccine against Covid-19