How worried should we be about the India variant?
In recent weeks the UK has recorded a rapid rise in the number of Covid infections caused by a variant of the virus first detected in India last year. Public health officials and scientists are investigating the increase to understand what it means for the country’s epidemic and the roadmap out of lockdown.
What is the variant?
Three notable variants have arisen in India, but the one drawing most attention is named B.1.617.2. Genomic surveillance spotted the variant in the UK in March. Last week, it was declared a “variant of concern” by Public Health England (PHE) after laboratory and epidemiological studies found it may be more transmissible. Cases of the variant have risen sharply in the UK since April. It has been found in travellers from India and contacts of those travellers (often people in the same households), but is less prevalent in the wider population.
How transmissible is it?
Scientists are still working on this. PHE has said the variant is at least as transmissible as the Kent variant that fuelled the UK’s devastating second wave this year and has spread around the world. A preliminary assessment by Tom Wenseleers, a professor of evolutionary biology at the University of Leuven in Belgium who worked with UK scientists on the spread of the Kent variant, suggests B.1.617.2 may be 60% more transmissible than the Kent version. Data on the new variant is still patchy though, and estimates of transmissibility are highly provisional.
Rowland Kao, a professor of veterinary epidemiology and data science at the University of Edinburgh, said there was “good evidence” the variant was spreading faster, but that does not necessarily mean it is more transmissible. “There is likely to be some influence of the communities where it entered the country,” he said. For example, if the variant gets into communities that tend to have larger households, or where many jobs are hard to do with good social distancing, that alone could boost transmission.
Does the variant cause more severe disease?
There is no evidence yet that the India variant is inherently more deadly than the Kent variant, but again scientists would like better data to examine this. The main concern is that the India variant causes infections to spread faster, leading to a larger third wave of disease and more hospitalisations and deaths.
Do vaccines work against the new variant?
Almost certainly, but how well is not clear. Laboratory studies by Prof Ravi Gupta at the University of Cambridge suggest mutations in the B.1.617.2 variant may make it partially resistant to antibodies. He found that the neutralising effect of antibodies induced by one dose of Pfizer vaccine was four to six times weaker against virus with the L452R mutation found in B.1.617.2. But this may not be a big problem. People who have been vaccinated, or infected with the virus, may well have high enough antibody levels to protect them. The immune system also fights the infection with T cells – whether these are less potent against the variant is another unknown.
What should we do?
There are several options. It may be possible to speed up vaccinations. Another is to target areas with large clusters and vaccinate more heavily there. Younger people are more likely to spread the virus as they tend to have more contacts, so vaccinating them earlier than planned could have a big impact on curtailing the spread. It is not a simple decision though. Mark Woolhouse, a professor of infectious disease epidemiology at the University of Edinburgh, believes the first priority should be to ensure no older or otherwise vulnerable people are left unprotected in those areas. Local lockdowns or “circuit breakers” are other interventions that could quell the rise in cases.
If vaccines cannot be rolled out faster or targeted to outbreaks, the government could slow the easing of restrictions until more data is in and vaccine coverage is higher. While the UK’s vaccine programme has been going extremely well, there are still millions of people unprotected. Christina Pagel, a professor of operational research at University College London and a member of Independent Sage, favours the slowing down approach to reduce the risk of having to reimpose tougher lockdown measures later. Kao has similar concerns: “It’s better to be cautious now rather than wait until we are sure because the worst case is hard to rule out.”
The rise in cases and the lack of solid data leave ministers in a catch-22 situation, Woolhouse says. “The difficulty for the government, and I really do sympathise with them over this, is that if the variant is more transmissible, and if we need to take more measures, we need to take them sooner rather than later, and we will almost certainly have to do that in the absence of robust information about whether we really need to do it,” he said. “If we do need to act, it’s much better to do it now, so it’s a genuine difficulty.”
Could it derail the roadmap?
While the variant may be more transmissible, if it does not cause more severe disease or evade vaccines to a great extent, then the outlook is still broadly positive. “We can still expect to be heading towards relaxation,” said Kao. “It is possible that this will occur at a slower pace, especially in some areas and with some regional prioritisation of vaccination.”