Vaccinated People With Previous Infection Might Be Immune To Various Variants Of COVID19 Virus

Experts from the US have done a study to understand the efficiency of the first generation vaccines in preventing different variants of the SARS-CoV-2 virus. They have enrolled people who have been infected with the virus in the past in their study. The SARS-CoV-2 virus leads to COVID19 disease. The virus has claimed the lives of around 3.91 million people across the world. The virus continues to be a threat to global health. The team of experts has tested the levels of neutralizing antibodies against different strains of the virus before and after two doses of the Pfizer-BioNtech vaccine in ten people who have been diagnosed with the disease before vaccination. Experts have compared neutralizing titers with the neutralizing titers of people who have not been infected with the virus before vaccination. Scientists from Oregon Health and Science University in Portland have shown that vaccination has been able to shoot up pre-existing levels of antibodies by 10 fold in people who have been infected earlier as compared to people who have not been diagnosed with the disease. The spike protein in the SARS-CoV-2 virus helps it to infect host cells. The spike protein attaches to the human host cell receptor angiotensin-converting-enzyme 2 (ACE2) through its receptor-binding domain (RBD). RBD is the main target point of neutralizing antibodies that are developed after an infection or vaccination.

The study has shown that vaccination has shot up the level of neutralizing antibodies in people who have been infected earlier against the original strain and three other strains of the virus. Experts have seen that neutralizing titers in people with past infection have been five times higher against the B.1.1.7 strain that has been found in the UK for the first time. Neutralizing titers in people with past infection have been more than six times higher against the B.1.351 strain that has been found in South Africa. It has been more than four times potent against the strain that has been found in Brazil known as P.1. Since the COVID19 pandemic has started in 2019, many experts have come up with a wide range of vaccines that can protect people against the deadly virus. These vaccines have been proven to be effective in their clinical trials. These vaccines have been approved for emergency use in many countries.

With the large fraction of many communities gaining natural immunity against the virus via prior infection, the vaccination plans have raised the odds that a high level of herd immunity might be achieved soon. However, the surfacing of various strains of concern (VOCs) of the virus has created a doubt in experts’ minds. These strains have spike mutations that can shoot up the binding ability of the virus to host cells and its ability to spread. Experts have noted that there has been no major change between the post-vaccination neutralizing antibody titers against the B.1.351 variant of the virus in people who have been diagnosed with the disease earlier and those against the original strain in people who have not been infected ever. The study has shown that the first generation COVID19 vaccines have been quite effective against some deadly strains of the virus when it has been given after the first infection.