A second wave of Covid-19 and is lockdown the answer?
- Large parts of Europe are in a second lockdown as a new wave of infection sweeps through the continent.
- Cases in the US are smashing new records.
- But overall numbers in India are falling — for reasons not yet fully clear.
Is there any precedent from previous pandemics that strengthen the argument for allowing naturally acquired herd immunity in Covid-19?
- When a new pathogen enters a territory where nobody has any immunity, it can cause devastation.
- As soon as some immunity builds up in a population, our relationship with the pathogen changes.
- Typically, immunity keeps the risk very low.
- Example is of the Zika virus: it came to Brazil, there was a spate of microcephaly, and now there’s widespread population immunity — this doesn’t mean Zika has disappeared, but the risk is low.
- There are strong paradigms and examples of how herd immunity protects the population.
How important is herd immunity as a solution, when we are still learning about how long antibodies against Covid-19 last, and some countries are already spotting reinfections?
- Antibodies wane, so you cannot use them to declare what proportion of the population has been exposed to the virus. They are the foot soldiers and only a part of the various things we recruit to fight the virus.
- Antibodies are only a marker that you have recently been exposed.
- They do not reflect what’s going on with the immune response, so it’s wrong to say that the decay of antibodies means that protective immunity is decaying.
- Previous exposure to other coronaviruses also gives you some immunity to this new virus, so it’s a complex landscape.
When compared with Nordic neighbours, Sweden’s herd immunity model had limited dividends in terms of economic gain. How does it look now, as Europe battles a second wave?
- It’s unfair to judge the Swedish model in comparison to other Nordic countries.
- It’s also not fair to judge it on the basis of how many deaths have occurred within that peak.
- The truth is, following the same kind of strategy, the level of deaths Sweden achieved was similar to the UK — a more fair comparison.
- Sweden made the same mistakes of not protecting its care homes as well as it might have done — the Swedes would be the first to admit you can learn from what happened there.
- Denmark and Norway both managed to control the virus and so, not surprisingly, have had fewer deaths.
- We’ve also seen approaches like that of New Zealand, which imposed stringent restrictions to eradicate cases.
- New Zealand’s strategy was to close its borders and hunt down and kill every virus that managed to cross.
- Instead of considering the huge costs of a lockdown and how it’s going to send 130 million people into starvation (around the world), people have a monocular vision focused on the virus and stopping deaths from it.
So, what approaches globally are good examples of how to best handle this pandemic, especially for a country like India?
- Sweden is obviously a good example — not going into full lockdown, but trying at the same time to institute measures with the idea of protecting the vulnerable.
- Look at slums like Dharavi — the virus passed through it, lots of people got infected (but) the deaths were low, probably because, among the infected, most people were young.
- I think there’s a possibility in India that the older generation is more protected because they have some immunity through regular exposure to young people.
- Shutting down the economy is, almost everywhere, going to cause more harm, and going to disproportionately harm the poor and the young.
How far is India from achieving herd immunity?
- Many pockets in India have already clearly achieved herd immunity, because infection levels are falling naturally.
- In India, there are studies where you get 60-70% antibodies in particular localities.
- Those are areas where people have been recently exposed, and it has overshot the level required (for) herd immunity.
- Furthermore, not only do antibodies decay, another thing we know is that not everybody makes antibodies.
- I suspect in India, because of continuous exposure to coronaviruses, people have more residual immunity from cross-immunity (which means immunity developed from another coronavirus would help protect against the new coronavirus)
Data suggests around 10% of deaths in India are of those aged 26-44. Which age groups should be allowed to live their lives normally, and with what caveats?
- The data needs to be looked at carefully.
- We know there’s an age link, and in terms of who should go back to work, certainly the data from the UK and many other countries suggest people in that age bracket (26 to 44) have very low risk.
- In the UK, (Prof) Carl Heneghan (of Oxford University) has done a thorough analysis of deaths. Even in the elderly, the people who have died were people with some form of comorbidity.
- The likelihood of dying, if you’re fit and healthy, is quite low, even among the elderly. But it’s going to vary from region to region.
- There are all sorts of ways in which younger people also need to think about protecting themselves.
- Reducing exposure, even among those who are young, should still be part of the thinking.