Coronavac: over 60 need 3 doses to be considered protected, says Opas

People vaccinated with Coronavac, from the Chinese laboratory Sinovac, must receive a third dose if they are 60 years or older to be considered fully vaccinated, according to PAHO (Pan American Health Organization).

The Sinovac vaccine has been widely used in Latin American countries.

In addition to Brazil, they also applied Coronavac, to a greater or lesser extent, Chile, Colombia, Ecuador, El Salvador, Mexico, Dominican Republic, Paraguay, Uruguay and Venezuela.

“All those aged 60 and over who have received Coronavac need to obtain a third dose to be considered fully vaccinated,” PAHO Deputy Director Jarbas Barbosa said in an interview on Wednesday (8).

This guideline advances in relation to the scheme proposed by PAHO and the WHO, which previously indicated that two doses of Coronavac constituted the complete inoculation scheme, although they recommended a third dose for risk groups such as over 60 years and immunosuppressed, as it has long been over time a drop in antibodies is observed.

Countries such as Brazil, Colombia or Uruguay have already implemented the booster dose at least for groups at higher risk, although in some places the population’s response to the third dose has been lower than to the first two.

In some countries, the third dose booster has been done with other vaccines (read below about third dose in Brazil).

“The last time I reviewed the data, (…) in Brazil, probably 60% of this population had already received the third dose. Therefore, many people still need to receive the third dose to be fully vaccinated,” added Barbosa.

On the same occasion, Barbosa also referred to those vaccinated with doses produced by the Chinese laboratory Sinopharm —these applied in countries like Argentina, Cuba, Mexico, Nicaragua and Peru, among others.

He said that “all those over 60 years who received vaccines produced by the Sinovac or Sinopharm laboratories need a third dose”, although he did not clarify whether for those vaccinated with Sinopharm the vaccination schedule will only be considered complete when the booster is received.

“Studies clearly show that after six months immunity starts to decline significantly among the elderly,” he added.

According to Barbosa, the WHO recommendation after listening to the independent vaccine group (Sage, its acronym in English) is that all immunocompromised patients receive a third dose of the vaccine with an interval of one to three months between the second and third dose.

All those over 60 years who were inoculated with Sinopharm or Sinovac ​​ “can receive a booster of any available dose with an interval of three to six months from the second dose”, said the deputy director of PAHO.

Third dose in Brazil

In mid-November, the Ministry of Health announced that all Brazilians over 18 are able to take a third dose of the vaccine that protects against Covid-19.

Until that time, the booster took place after six months and was only indicated for individuals over 60 years old, health professionals and immunosuppressed (people with problems in the immune system).

Minister Marcelo Queiroga assured that the country has enough doses to offer this third application to all adults between November 2021 and May 2022, at 38 thousand health centers throughout the country.

At the time, when asked about the type of immunizing agent that will be used as a booster, Queiroga said that the ministry continues to bet on the heterologous scheme.

“The preference is for this additional dose to be a different vaccine, which is a decision based on data and scientific evidence,” he explained.

In other words, this means that anyone who has taken two doses of AstraZeneca will receive a third from Pfizer and vice versa.

The trend, according to the minister, is that most adults receive the product from Pfizer as a third dose, because the immunizing agent from AstraZeneca was the most used as the first and second doses in this age group over the past few months.

“In the event of a possible shortage of Pfizer’s vaccine, which should not happen, we will be able to use another vaccine platform, preferably of a different type than the one used in primary vaccination”, completed Queiroga.

Physician Rosana Leite de Melo, extraordinary secretary for Covid-19 at the Ministry of Health, said that Brazil has already guaranteed enough vaccines to apply the third dose and is already evaluating the need to buy more units for an eventual fourth dose in the elderly in the second half of 2022.