THE situation in India continues to worsen, with more than 20 million cases of covid-19 recorded and health systems overwhelmed. But there is nothing unique about India that means it alone could face such a crisis. Around the world, country after country is being hit by surging coronavirus cases, driven in part by new variants that are harder to control.

The pandemic is accelerating across South America, and cases are rising in many African countries too. In most low and middle-income nations, few people have been vaccinated against the coronavirus, compared with some high-income countries, where high vaccination rates are allowing restrictions to be eased. Add to this the fact that many lower-income countries don’t have the medical capacity to deal with a huge new wave, and you have a catastrophe in the making.

There has been much discussion of vaccination in relation to easing India’s plight. One thing we can say, though, is that vaccines alone won’t halt a surge in cases. Chile saw case numbers soar even as it vaccinated nearly half of its population, for instance. In Israel and England, vaccination has been used as a way out of lockdown, with the lockdowns used as the main way to control surging case numbers.

So far, only one country has managed to vaccinate its way out of a potential new wave of covid-19. In the US, the vaccine roll-out appears to have been ramped up in time to curb a surge due to the B.1.1.7 variant imported from the UK.

The issue is that to reduce the spread of the coronavirus, the majority of a population needs to be fully immunised with a highly effective vaccine. That takes time even with ample vaccine supplies, and India has neither time nor vaccine supplies on its side. In the meantime, another national lockdown, however difficult, seems necessary.

The crisis in India is a warning. Until many more countries have been able to vaccinate most of their populations, what has happened in India could occur elsewhere if rising case numbers are ignored. Those countries must plan for the worst and the global community must be ready to help.

India’s “double mutant” coronavirus variant, more accurately known as B.1.617, is a variant of SARS-CoV-2 that is common in India and present in several other countries.

Media reports claim it is the main cause of India’s second wave, but this hasn’t been formally established. It may be one of several variants playing a role.

Calling it India’s double mutant is misleading on two counts. First, B.1.617 has around 15 mutations. Double mutant refers to the fact that it has two mutations of particular concern in the outer spike protein of the virus, which the virus uses to enter cells. These mutations may make antibodies to older variants or existing vaccines less effective, although initial studies suggest that the Covaxin and Oxford/AstraZeneca vaccines used in India still prevent infection by B.1.617.

Second, the two mutations are not unique to B.1.617. Other variants with both mutations have been found elsewhere.

B.1.617 has reportedly become the most common variant in Maharashtra state, suggesting it is more transmissible than other variants present there. However, in parts of India, other variants are more common.

The number of cases of the B.1.617 variant detected in the UK rose sharply recently, but almost all were in people returning from abroad. Since 23 April, the UK has banned travel from India to try to prevent further imports.

Some B.1.617 viruses have an additional mutation called V382L in the spike protein, often reported as a “triple mutant”, but there is no evidence that this variant spreads more readily or is deadlier.