Uncategorized

According to a new study, those with blood group A, B, and Rh factor (Rhesus factor) positive are more “vulnerable to Covid-19 infection” than those with blood group O or AB and Rh negative. The study was carried out by specialists at Sir Ganga Ram Hospital in Delhi.

A statement released by Sir Ganga Ram Hospital (SGRH) on Tuesday reveals that the research was conducted on a total of 2,586 Covid-positive patients. They tested patients who were admitted to the hospital from April 8 to October 4 in 2020 through real-time PCR (RT-PCR). The study was carried by the Department of Research and Department of Blood Transfusion Medicine at the SGRH. It has been published in the November 21 edition of ‘Frontiers in Cellular and Infection Microbiology’.

The study says that “people having blood groups A, B and Rh+ are more susceptible to Covid-19 infection whereas (those with) O, AB and Rh- are at lower risk of Covid-19 infection.” The research also claims that “there is no association between blood groups, and susceptibility to severity of disease as well as mortality.”

The Rh factor or the Rhesus factor is a protein that is present on the surface of red blood cells (RBCs). Simply put, the positive or negative sign next to our blood groups denotes the Rh factor. So, if you have a positive blood type, this means that the blood cells have the Rh protein. If you have a negative blood type, then the blood cells lack the Rh protein.

“Severe acute respiratory syndrome coronavirus 2 is a new virus, and it is unclear whether blood groups have any impact on Covid-19 risk or progression. Therefore, we investigated the association of ABO and Rh blood group with Covid-19 susceptibility, prognosis, recovery time, and mortality in this study,” Dr Rashmi Rana, Consultant, Department of Research, SGRH, said in a statement. The patients also had to go through a follow-up till their last date of admission as either discharged or deceased during the study, the hospital authorities said.

Little is known about the Omicron variation of the SARS-CoV-2 virus’s behaviour, but as a full virion (whole viral particle) vaccine, Covaxin may have a higher chance of being successful against it than other, more focused vaccines, according to a senior ICMR official.

Omicron, the most recent strain of the virus discovered in South Africa, is thought to be the virus’s most modified form yet.

“A lot of what we are saying about vaccines and the new variant right now is conjecture. We are assuming a lot about the structure function relationship of the virus and the vaccine. But it is a plausible conjecture to say that the virus may have less chances of escaping the immunity given by Covaxin than for other more targeted vaccines where the focus is principally on the spike protein,” Dr Samiran Panda, head of epidemiology and infectious diseases, ICMR, told ThePrint.

The mRNA vaccines, such as those of Pfizer and Moderna, are designed to produce a portion of the spike protein inside the cell by transcribing it from the codes contained in the piece of mRNA. Thus the body learns to identify the virus using that part of it. However, Omicron has about 50 mutations, many of them on the spike protein and its receptor binding domain (RBD).

“The RBD had two mutations in the Delta variant and here there are 10. If the structure of the domain changes then how well the lock and key arrangement works with other vaccines is a question. In the case of Covaxin it is a little like a Bruce Lee assault, when three different and potentially fatal sites are targeted at the same time,” Panda said.

However, he conceded that mRNA vaccines have the advantage that they can be tweaked very quickly to tailor them to variants. The AstraZeneca vaccine manufactured in India as Covishield by the Serum Institute of India also uses genetic instructions for building the virus’s spike protein to familiarise the body with the SARS-CoV-2 antigen.

‘Seems to be more transmissible’

The World Health Organization maintains that it is not yet clear whether Omicron is more transmissible. However, Panda said that going by the rapid increase in case numbers in South Africa it does seem that it is more transmissible.

“You have to understand that all our vaccines are disease modifying and not disease preventing. I have been talking to my colleagues in South Africa and what we have come to know is that even in unvaccinated people infected with Omicron, the disease is mild. However, going by how fast cases have increased in South Africa, it does look like we are dealing with a more infectious variant,” he said.

Another senior government official, also a member of the National Expert Group on Vaccines Against Covid-19 (NEGVAC), told ThePrint that “it is possible” that Covaxin, being a whole virion vaccine, would work better against this latest variant. “Do wait for full characterisation of Omicron. We need to be sure in the laboratory as well,” he said.

Covaxin was approved with variants in mind

In January this year, when Bharat Biotech’s Covaxin was first approved by the Drug Controller General of India (DCGI), efficacy data for it was not available. However, one of the considerations that had influenced the decision was the hope that as a whole virion vaccine, it would work better against emerging variants.

“We know that the virus has undergone mutations, including in the spike protein. Pfizer has said that they will need six weeks to modify the vaccine. But because Covaxin is basically the whole virus killed, it is more likely to act against the mutant strain too. Simply put, if there are say 1,000 points in a vaccine, of which two have mutated, this (vaccine) is still going to have 998 points to generate a response, unlike others such as mRNA vaccines, which target specific areas and may not work as well when those areas mutate,” Dr Balram Bhargava, Director General, ICMR, had said then.