translated from Spanish: U of Chile study: Pfizer and Sinovac vaccines generate “a powerful immune reaction” in the population

The study of the University of Chile that was carried out on more than 64 thousand people in different cities of the country (who were applied rapid blood tests showed a high presence of immunoglobulin G (IgG) against the SARS-CoV-2 virus in the population that was vaccinated with Sinovac and Pfizer.The study that was published in the journal The Lancet Infectious Diseases and according to the data provided shows that two weeks after having been vaccinated with Sinovac and Pfizer.The study that was published in the journal The Lancet Infectious Diseases and according to the data provided shows that two weeks after having been vaccinated. inoculated with the second dose of Sinovac the positivity of the IGg antibody in that group reached 77%, on the other hand, those who applied the second of Pfizer exceeded 95%. Dr. Miguel O’Ryan, from the Faculty of Medicine of the U of Chile, said that in the group vaccinated with Sinovac “we begin to see a slow drop in positivity, reaching levels that stabilize at around 46%.” While with Pfizer “it is sustained over time”, remaining above the 90% mentioned above, because he said that “a fall is not noticeable as it was observed for the Sinovac vaccine, in such a way that there is a differential response between one vaccine and another (…) Sinovac falls in time, Pfizer does not fall, and that is independent of all other factors.” We must be very cautious with the interpretation of these results”, since he emphasizes that “the decrease in IgG immunity does not necessarily imply by itself the decrease in protection”. “While for Sinovac you see an IgG drop that doesn’t necessarily mean protection is falling. That initial 75% is saying that there was an immune response, that there are other immune mechanisms that were activated as well, and those other immune mechanisms may be conferring protection well beyond what this drop in antibodies might appear.” In this way, O’Ryan argues that “both vaccines generate a powerful immune reaction” and that “that initial response of 75% in people with Sinovac vaccine is a very good vaccine response, closely associated with protection against infection, and that has played a very important role in the control of the pandemic in our country.” The pattern of antibody drop for Sinovac is adding elements to say that the booster dose has a research- and science-based underpinning,” he added.

Original source in Spanish