In the vaccination against Covid-19, two manufacturing methods have been used: messenger RNA vaccines, such as Moderna and Pfizer, and more classic inactivated virus vaccines, such as Chinese products produced by Sinovac (Coronavac, for example). By studying 1,442 people who had received two doses of the latter type, and comparing them to the results of subjects vaccinated with Pfizer, scientists from Hong Kong realized that they made it possible to produce 10 times less antibodies, reveals The Lancet Microbe.
Some territories have been vaccinated with the type of vaccine produced by the Chinese laboratory Sinopharm, such as the Seychelles. When others, like Israel, have benefited from the Pfizer. These two spaces are interesting to compare because their populations are mostly vaccinated. However, a much larger wave of new infections (including among vaccinated) has been observed in the Seychelles, when the virus seems to be circulating less quickly in Israel. This example raised fears of a lesser effectiveness of the classic vaccine against Covid-19.
Antibody levels similar to former Covid-19 patients
That said, vaccines from Chinese laboratories would still reduce the risk of developing a serious form of the virus. On the other hand, the quantity of neutralizing antibodies produced by vaccination is not enough to discredit a vaccine. Especially since scientists have observed that post-vaccination antibody levels were substantially the same as those developed naturally by subjects who had previously contracted the diseaseand are considered to have some immunity.
While this confirms that messenger RNA vaccines are more effective, in that they have better outcomes against contracting the virus, it does not mean that inactivated virus vaccines are ineffective. Some countries that have benefited from it are already opting for a third dose, to deal with the more contagious variants.
Source : Comparative immunogenicity of mRNA and inactivated vaccines against COVID-19, The Lancet MicrobeJuly 2021.
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