A study conducted by scientists from the Juan H. Jara National Institute of Epidemiology and the Leloir Institute Foundation (FIL) showed that the neutralizing ability of antibodies generated by Sputnik, AstraZeneca and Sinopharm vaccines in people over the age of 60 decreased from from to three to nine times at 6 months, demonstrating the need to apply a booster dose, particularly important in this context of increasing cases.
This is a survey conducted in collaboration with PAMI which sought to measure the impact of vaccination on people institutionalized in long-term residences, which was attended by 851 volunteers with an average age of 83 from La Plata, Lanús and Mar del Plata. March and November 2021.
“This study was born out of PAMI’s need to monitor the adult population and follow up on vaccinated people. For this it has requested the collaboration of the National Institute of Epidemiology (INE) and the Fundación Instituto Leloir (FIL),” said the biologist and professional of Conicet, Pamela Rodríguez, one of the main authors of the work published in the journal “Le frontiere dell ‘immunology”.
For his part, the director of the FIL Serology and Vaccines Laboratory, Andrés Rossi, stressed that “the main contribution of the work was to demonstrate that the three platforms used in the country managed to generate the immune response; Furthermore, we determined that these levels decrease over time and that, as seen in the general population, prior exposure to SARS-CoV-2 elicits a greater response.”
Anti-Spike IgG antibodies were measured with the Covidar kit (also developed at FIL) and the study was able to determine that their neutralizing capacity decreased three- to nine-fold 6 months after initial vaccination for all the platforms.
Furthermore, the neutralizing ability against Omicron was 10-58 times lower than the ancestral B.1 (so-called Wuhan strain) for all vaccine platforms at 21 days after dose 2 and 180 days after dose 2. dose 1.
“This difference in neutralizing capacity between the B.1 and Ómicron ancestral strains shows that the pandemic is a dynamic phenomenon and, as such, requires response strategies to be dynamic as well. This is why we share the decision of the authorities to implement strengthening strategies to improve the protection of the population,” Rossi said.
And in this sense he underlined that «while in the country there are already those who are receiving a 5th dose (or third booster) of vaccines, a large majority still have the fourth pending; At this time when there is a significant increase in cases, it is important to apply the corresponding doses to complete the scheme”.
