BENGALURU: While the new strain of SARS-CoV-2 that emerged in the UK has caused concern about the implications for immunisation, manufacturers and experts say the mutation is “highly unlikely” to reduce vaccine efficiency. Union Health Minister Dr Harsh Vardhan said during a press conference in Delhi on Thursday that the vaccines being developed are unlikely to be affected by the new mutation. “If infections occur (after innoculation), they would be milder,” he said.
Karnataka Health Minister Dr K Sudhakar said there would be no impact on the Centre’s plans to roll out vaccines and that the state is prepared for the immunisation programme and is awaiting vaccine approvals. Pune-based National Institute of Virology is reportedly monitoring the new strains from other countries closely and is said to submit its data to the Indian Council of Medical Research soon.
How the vaccines work
“Spike protein is a crown protein on the virus which comes in contact with human cells to gain entry and infect. However, the new variant has mutations in the spike protein that the three leading vaccines are targeting,” said a renowned virologist who declined to be named. The spike protein – made up of a chain of amino acids – on the surface of SARS-CoV-2 (the virus that causes Covid-19) binds to ACE2, a type of protein on the surface of human cells. The 501st position on the chain of amino acids has changed to tyrosine (represented by the letter Y) from asparagine (represented by the letter N). So, the mutation is called N510Y, the virologist said.
Still, it is unlikely the mutation would impact vaccines developed by Moderna, Pfizer BioNTech, and Oxford-AstraZeneca. “These vaccines are made to work on a broad spectrum and produce antibodies against many regions in the spike protein, so it’s unlikely that a single change would make it less effective,” he said. Bioethics researcher Anant Bhan said, “As of now, there is no indication that the vaccines will not be efficacious. Lab tests and ongoing studies should give us some data. Since mass vaccination has begun in the UK, we should find out if vaccination is able to protect against the new strain through a natural experiment. Closely watching public health surveillance and genomic surveillance would be useful.”
Meanwhile, in a recent statement, Pfizer said that when SARS-CoV-2 first emerged a year ago, it was clear there was more than one strain and that it was mutating as it spread. It said SARS-CoV-2 is an RNA virus with “exceptionally high (mutation) rates” because the enzymes it uses for replication are prone to errors. A virus survives by invading cells and using the latter’s cell machinery to make copies of itself and spread.
“One of the reasons Pfizer and BioNTech chose to utilize a mRNA platform is because of the potential for the flexibility of the technology in comparison to traditional vaccine technologies, including the ability to change the RNA sequence in the vaccine, should a strain emerge that’s not covered by the current shot,” Pfizer said.
What this means is: Unlike most other vaccines which introduce a weakened or or inactivated (dead) germ into our bodies, mRNA vaccines give instructions to human immune cells to make a harmless piece of a spike protein. The immune system then recognises this as foreign, and begins making antibodies to get rid of it. So in case there is a mutation in the spike protein of SARS-CoV-2, scientists can design new instructions for the mRNA vaccines (mRNA is short for messenger RNA).
Ugur Sahin, CEO of BioNTech told the media on Wednesday, “Though it is likely that the vaccines will work on the new strain, if needed, the beauty of the messenger technology is that we can directly start to engineer a vaccine which completely mimics this new mutation. We could be able to provide a new vaccine technically within six weeks.”
However, senior epidemiologist and advisor to the state’s Covid task force, Dr Giridhara Babu remained cautious, “Most of the vaccines are directed against the spike protein and are thought to be of broad spectrum coverage. The vaccines are being investigated for effectiveness against the mutant strains of the virus. The jury is still out.”
Source: The New India Express