The global number of COVID-19 cases and deaths has fallen for the sixth week in a row, marking a sharp downward trend in the pandemic. So much so, in fact, that many countries are planning a return to something resembling “normality” by June or July.
A realistic marker for the end of the pandemic may be when a country has no more COVID-19 deaths than it would have from flu.
But when the end of the pandemic will actually come is harder to pin down. One measure could be zero transmission, but with the likelihood that COVID-19 will become endemic that seems far from reality. The criteria the World Health Organization (WHO) uses to declare pandemics – and then to de-escalate them to delineate when they have ended – can be complicated. WHO has to be sure that declaring the end of a pandemic doesn’t mean that everyone becomes so relaxed that the virus rebounds.
Even widespread vaccine coverage may not be enough and it’s not clear we will ever reach 70-80% vaccination rates in countries – the estimated proportion of people who need to be immune to COVID-19 to stop transmission. A realistic marker for the end of the pandemic may be when a country has no more COVID-19 deaths than it would have from flu – in the USA, this is 100 deaths a day.
Although we’re not at that point yet, here are some reasons to think the pandemic is slowing down.
In the UK, 21.1 million people have had at least one dose of a COVID-19 vaccine, and in the USA, this number is 76.9 million. This week Côte d’Ivoire and Ghana became the first countries to start vaccinating people through COVAX, an initiative between Gavi, WHO and the Coalition for Epidemic Preparedness Innovations (CEPI) to ensure equitable access to COVID-19 vaccines worldwide. However, vaccine supply isn’t enough – it needs to be met with vaccine demand, and India is a case in point. In January, only 8.4 million people turned up to be vaccinated even though the country had enough supplies to vaccinate more than four times that number. And of the nearly 200,000 people to receive their first dose on the first day of vaccinations in January, only 4% returned for their second dose. The low turnout may partly have been due to COVID-19 cases and deaths falling (though health workers refusing vaccines, and a concern that vaccine development was rushed, no doubt didn’t help). But now, India seems to be seeing an uptick in cases again, potentially taking the country into a second wave.
After a spike in cases, due to winter in the northern hemisphere and holiday celebrations, many countries went into some form of lockdown of varying severities (in some places children have been kept off school for weeks or months), which seems to be paying off with downward trends in COVID-19 cases.
Seasonality does seem to have a role in COVID-19 infections, as with other respiratory infections. Some scientists have suggested that vitamin D and sunlight may play a role in reducing COVID-19 transmission. However, this isn’t entirely borne out, as evidenced by a rise in cases in Europe last year in the height of summer.
Wearing face masks and physical distancing has become part of everyday life, even in countries in the west where wearing a face mask was almost unheard of outside hospitals. Although there have also been objections to restrictions in some countries – the USA for example has seen protests against wearing masks – in many places, this adherence is due to people complying with measures to avoid penalties or fines, as governments have increased oversight. It is likely of course that when people are in crowded places, such as beaches, they are not as good at distancing, but the risk of transmission tends to be lower outdoors.
Although we are a long way from achieving herd immunity anywhere in the world, the number of people who have been infected is rising – which some describe as the virus “running out of bodies”. In India, for example, one in five people on average have antibodies to COVID-19, though this number rises to 60% in cities like Mumbai, Delhi and Bangalore. It’s important to note though that while it is still not clear how long natural immunity lasts, so any protection occurring right now from previous infections may be short-lived.
As encouraging as this steep decline in cases is, scientists warn it would be foolish to become complacent now. New variants of COVID-19 are continuing to emerge, and it’s not clear how this will affect the direction of the pandemic, or whether they will mean some vaccines are less effective. Also if seasonality and lockdowns are behind the drop in cases, then as soon as the seasons change and restrictions are eased, cases could go up – although by this time, hopefully vaccine coverage would be widespread enough to mitigate it.