Arushi Bidhuri
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Written By: Arushi Bidhuri | Published : July 9, 2021 6:26 PM IST
Gamma variant, which was first spotted in the Amazon City of Manaus in December 2020, contributed to an increase in Covid cases in Brazil. It strained the country's health system and led to oxygen shortages. So far, it has been found in at least 72 countries. Previous research has indicated that it can evade antibody neutralization. Adding to the evidence, a new study has found that even though two doses of China's CoronaVac vaccine give 83.5 per cent protection against symptomatic Covid-19 illness, but is less effective against Gamma variant.
According to two separate studies published in the Lancet, two doses of the CoronaVac vaccine from China provide 83.5 per cent protection against symptomatic Covid-19 illness, however, the vaccine's antibodies are less effective against the Gamma (P1) strain. The study found that antibodies from all of the people, who were both partially and fully vaccinated with CoronaVac, did not affect the P1 variation.
The P1 variation, on the other hand, was still susceptible to antibodies in the plasma of individuals who had two immunisation doses (second dosage 17-38 days earlier), although to a lower amount than the B lineage virus. The P1 variation, which includes 15 distinct mutations, was identified in Manaus, Brazil, in early January 2021.
Jose Luiz Proenca-Modena, from the varsity's Laboratory of Emerging Viruses, said, "Neutralising antibodies are an important component of the immune response against SARS-CoV-2. Therefore, the capacity of the P1 variant to evade antibodies present in the plasma of CoronaVac-immunised individuals suggests that the virus can potentially circulate in vaccinated individuals -- even in areas with high vaccination rates."
Proenca-Modena said that as a result, neutralizing antibodies may not be the primary mechanism in decreasing illness severity, the T-cell response might also play a role. According to a phase-3 trial headed by researchers from Hacettepe University Medical School in Ankara, Turkey, CoronaVac generates a significant antibody response in 90% of individuals who get the vaccine. However, the antibody response may reduce as men and women get older.
The coronaVac vaccine was developed by Sinovac Life Sciences, which can be stored and transported at 2-8 degrees Celsius, has been approved for emergency use in 22 countries. It makes use of a complete virus that has been inactivated. The vaccination causes the immune system to target the virus's harmless form and produce antibodies to resist it, resulting in protection. As per the researchers, one of the advantages of CoronaVac is that it does not need to be frozen, making it easier to carry and distribute.
Among the study participants (more than 10,000) in Turkey, no serious adverse events or fatalities were reported, with the majority of adverse effects being minor and happening within seven days following an injection. However, more study is needed to demonstrate vaccination effectiveness over time, in a larger group of people, and against new variations of concern, according to the scientists.
(with inputs from IANS)
