Chile has vaccinated 71% of the target population with two doses and more than 80% with one dose. (EFE / ALBERTO VALDÉS / ARCHIVE)
The Coronavac vaccine, from the Chinese laboratory Sinovac, is less effective against the Andean variant or lambda, one of the predominant strains in several Latin American countries, and against gamma and alpha, according to a study by the University of Chile released this Friday.
The research indicates that the lambda variant – the name given by the World Health Organization to the Andean or C.37 – is the one that most reduces the neutralizing capacity of the antibodies generated by Coronavac, reducing its effectiveness 3.05 times.
The virologist who led the study, Ricardo Soto, explained to Efe that most of the vaccines against covid-19 were designed with the reference of the ancestral lineage, that is, the original virus that started from Wuhan, and its response’ not guaranteed ‘with the new variants.
Likewise, it points out that the effectiveness of this vaccine against the gamma variant (colloquially Brazilian variant) was also reduced by 2.33 times and its usefulness against alpha (known as the British variant) decreased 2.03 times.
“If our body is presented with a changed virus, it is highly probable that not all the neutralizing antibodies that we have generated thanks to vaccines can combat it ,” said the academic.
When SARS-CoV-2 mutates, it changes its spike protein, he added, and sometimes “the new characteristics of this protein give the virus the power to escape antibodies.”
The study, published on the scientific dissemination platform medRxiv, was carried out in 75 patients vaccinated with the two doses from the Sinovac laboratory in Chile and did not consider the delta variant, which already circulates in at least 92 countries because it is the most contagious.
According to the Institute of Public Health (ISP) of Chile, the predominant variants in the country are the Andean and the gamma (Brazilian), the latter considered ‘of concern’ by the WHO, together with the alpha (British), beta (South African ) and delta (India).
“This could explain why there are people vaccinated with two doses of Sinovac – the one that has been mostly used in Chile – who are in serious condition due to covid-19 or who have died , something that should be corroborated,” the expert concluded.
Chile has experienced a wave of infections since March that put the health system on the ropes. Even though the country has deployed one of the fastest vaccination processes globally, intensive care units continue with an occupation of more than 90%.
More than 80% of the target population have received one dose, and 71% have already received both injections, mostly from Sinovac but also from Pfizer, CanSino, and AstraZeneca.