Science and Technology

Immutable fact: You need both a vaccine and a mask

M. Ramesh | | Updated on: Mar 14, 2021
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Amid the uncertainties over mutant strains and a possible second wave of infections, what’s certain is the need for continued vigil

A second wave of Covid-19 infection seems to be setting in in India. This raises a number of questions. Is this second wave due to mutations in the SAR-CoV-2 virus? To what extent does vaccination help? Is there any point in getting vaccinated if mutated viruses can still attack us?

There are no sharp answers yet — experts will likely proffer a ‘yes, but’ kind of reply. For instance, there is no clear evidence that the second wave is due to mutated viruses, but you never know.

But we know the direction we are taking is the right one. Yes, most of the mutations are not harmful, and, yes, vaccines offer protection against many of the mutated viruses; but, no, it cannot be said with certainty that a vaccinated person will not be infected by a mutated virus.

According to Indscicov.in, an Indian scientists’ initiative, “Evidence shows that most of the vaccines will confer some degree of protection from the currently evolved variants, though the combination of mutations carried in a particular variant, its prevalence in a region and the host immune response will ultimately decide the final efficacy of any vaccine.”

However, it is clear that even if a vaccine is not a chink-less armour, it reduces the opportunity for the virus to mutate further.

The best way to prevent mutations is to avoid giving the virus a chance to replicate, reducing the number of infected, notes Indscicov’s ‘hoax-buster’ resource. A vaccine may have less efficacy against a variant, but will still provide some protection and help halt transmission.

Second, a vaccine is broadly effective against variants also, as it raises an immune response in the hosts (us). “Even if one of the parts of the virus changes due to a new mutation, the vaccine will identify the other parts. This decreases the chances of newer variants escaping the vaccine,” Indscicov says.

A vaccine ought to be seen as the best shelter in a downpour of infections, even if a somewhat leaky one. Experts call for extreme vigil against the evolving variants of the virus.

Monitoring mutations

Rakesh Mishra et al argue in the perspicacious paper ‘SARS-CoV-2 genomics: An Indian perspective on sequencing viral variants’ that you need to keep a sharp eye on those with mutations in the spike proteins of the virus. Mutations on the spike — the horn-like protrusions that lock with ACE2 receptors of human cells to gain entry — can potentially facilitate better binding, as has been seen in the case of the D614G mutation, the paper says.

The paper identifies some of the mutations identified recently that are of concern — N439K, N440K, Q493K and E484K — as they seem to evade immunity. Of these, the N440K variant has been found in about 42 per cent of the samples from Andhra Pradesh and E484K in three samples from Maharashtra. Most of the other mutations are absent in the currently sequenced samples from Indian isolates and need to be actively monitored.

“Spike protein mutations have implications in Covid-19 surveillance and management, vaccines, therapeutics, and the emergence of reinfections. We need to have a focused approach towards monitoring the virus mutations,” says Divya Tej Sowpati, one of the authors of the paper.

India has not been sequencing SARS-CoV-2 isolates to full capacity, he says, having deposited only about 6,400 genomes (out of the over 10.4 million cases, or 0.06 per cent). The government has said it wants to sequence 5 per cent of all the positive cases.

Thus, as the second wave rolls in, India’s strategy needs to embrace two essential points. First, do more sequencing, understand emerging potentially harmful variants (‘mutation’ refers to changes within a cell; variant is a population with a particular mutation). The extent to which genomic surveillance can help control outbreaks is only limited by the availability of data and will be crucial to controlling the pandemic in the future.

Second, even as the vaccination programme is on — more vaccines are evolving in the labs that might be more effective than those in the market today in terms of shielding against the mutant viruses — there cannot be any slackening of vigil. “While vaccines may be very helpful, the masks, hand hygiene and physical distance are the most effective weapons we have against this pandemic,” says Surabhi Srivastava, another author of the study.

Published on March 14, 2021

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