Is COVID-19 effectively already endemic?
Will the pandemic go out with a fizzle or a bang? And what does “living with the virus” actually mean, and when will we get there?
8 July 2021 – by Linda Geddes
In the UK, it has been dubbed “Freedom Day”. On 19 July, most remaining COVID-19 restrictions will be lifted, and the world will see if high rates of COVID-19 vaccination are enough to keep hospitalisations and deaths from the disease at a stable, and acceptably low rate.
Some countries, such as New Zealand, have pursued an elimination strategy, keeping COVID-19 infections close to zero, but at the expense of heavy travel restrictions and snap lockdowns when outbreaks are detected. Others, including the UK, have taken the view that SARS-CoV-2 is endemic, meaning it will continue to circulate in the global population and trigger outbreaks, but that a certain number of infections and deaths are tolerable, provided they don’t spiral out of control and overwhelm the health system, as they have done during peak periods of the pandemic.
If fully vaccinated individuals do not transmit much virus, and vaccine coverage is high enough, then even if immunity wanes, regular booster doses could keep new variants at bay and see the virus eliminated in some regions of the world.
In other words, for the UK government and others like it, the end of the COVID-19 pandemic doesn’t mean zero COVID-19, but rather a transition to a more manageable and predictable level of disease that can be planned for, such as by allocating a certain number of hospital beds for COVID-19 patients, and running regular booster vaccination programmes and public awareness campaigns.
Though they may disagree on the timing, and the level of infections that might enable a lifting of the restrictions, this is also what many scientists mean when they talk about “living with the virus”. Once enough people have been vaccinated, any remaining restrictions on the freedom of individuals to travel and socialise, or on the ability of businesses to operate, can be removed, and normal life can resume – without the threat of health system collapse.
Knowing when we’ve reached this point is difficult, however, because we still don’t know to what extent immunity against the virus wanes over time, or the degree to which COVID-19 vaccines prevent transmission. Neither do we know the proportion of the population each country needs to vaccinate, or to have been infected, to reach herd immunity – where the whole community becomes protected, and not just those who are immune.
If fully vaccinated individuals do not transmit much virus, and vaccine coverage is high enough, then even if immunity wanes, regular booster doses could keep new variants at bay and see the virus eliminated in some regions of the world. If they don’t block transmission, or herd immunity can’t be achieved, the virus will continue to circulate, but – assuming those who are the most vulnerable to severe disease have been vaccinated – the number who experience severe disease may remain acceptably low.
Obtaining definitive answers to these questions will take time, and given the economic and wider health implications of COVID-19 restrictions, some governments are becoming increasingly impatient.
In the UK, where around two thirds of adults are now fully vaccinated against COVID-19 – including most of those over the age of 50 and/or with underlying health conditions – the government plans to lift all remaining restrictions on 19 July. Although the British Prime Minister Boris Johnson has acknowledged that this will initially lead to a large increase in coronavirus infections, his belief is that the UK vaccine rollout has “broken that link between infection and mortality.” So, although many people may get ill, hopefully very few will get severely ill or die.
Another uncertainty is the impact of new, more transmissible SARS-CoV-2 variants, like the Delta variant, which now accounts for most British infections and is rapidly gaining ground elsewhere. Many UK scientists would like to see a greater proportion of younger adults, and possibly many teenagers, fully vaccinated before the remaining restrictions are removed. This is both to reduce the number of severe infections in this age group, and because of concerns about “Long Covid”.
In Israel, where 56% of the population is now fully vaccinated, most domestic restrictions were lifted on 1 June, followed by the scrapping of a requirement to wear facemasks two weeks later. Yet it is now considering reintroducing some restrictions due to an increase in infections prompted by the Delta variant. Further variants may yet emerge that overcome the immunity afforded by vaccination to an even greater extent, delaying the end to this pandemic even further back. The chances of this happening are greater the longer a large proportion of the global population remains unvaccinated, and if infection rates in all countries remain high.
Ultimately though, we will need to learn to live with this virus. Based on what we know about previous pandemics, COVID-19 should eventually become less dangerous, and coronavirus infections more predictable. For instance, the influenza A virus that caused the 1918 Spanish flu pandemic, which killed more than 50 million people, remained in circulation for nearly four decades, although it became less virulent for most of this time. Almost all cases of influenza A since then, have been caused by descendants of that 1918 virus, but they are no longer as deadly, and the seasonal flu vaccine further reduces deaths and serious illness from flu.
Though Boris Johnson is planning a “big bang” reopening on 19 July, the wider pandemic is unlikely to end with a single big bang, and it is impossible to set a date for when normality can resume. Rather infections in different parts of the world may gradually fizzle to the point where we co-exist with COVID-19 in a perhaps tolerable, if imperfect, equilibrium.