From New Scientist:
"After two years of mass deaths, long covid, social distancing, cancelled weddings and isolated funerals, increasing numbers of political leaders are saying it is time to “live with covid”. In England, legal requirements for self-isolation and contact tracing look set to end on 24 March, while “Plan B” measures such as advice to work from home where possible will be lifted on 26 January. But just how close to the end of the pandemic are we? And what will the end really look like?
In a sense, the pandemic won’t end until the World Health Organization (WHO) declares it over, just as it first declared the coronavirus outbreak a pandemic on 11 March 2020. That won’t mean that the SARS-CoV-2 virus has been eliminated, however. Instead, the end will come when new infections occur at a fairly constant rate, as opposed to the big, unpredictable waves we have experienced so far.
This is the point at which covid-19 becomes “endemic”. The virus will still spread from person to person, but on average each infected person will infect only one other. This will mean fewer people being hospitalised, dying or developing long covid.
It is important to understand that there are different kinds of endemicity. “Whether it becomes endemic at a low level or a high level really matters,” says Christina Pagel at University College London.
A commonly cited benchmark is that covid-19 might become about as widespread and severe as influenza, which causes annual mini-epidemics in many countries. But this example illustrates the ambiguity of the phrase “living with covid”. While it is true that countries around the world “live with flu”, that doesn’t mean their governments do nothing. The UK and many other countries have an annual flu surveillance programme, and new vaccines are developed and given every year.
“There are all kinds of things we do to get flu deaths down, and we’ve massively got them down in the last 20 years,” says Pagel.
Nonetheless, were covid-19 to become similar to flu, that “would be a disaster for the UK”, says Pagel, because flu already strains the country’s national health services in winter.
If covid-19 ends up equally serious, it would still represent a significant and permanent increase in case load every winter.
Bringing the number of covid-19 deaths down depends on four factors: global vaccination rates, the evolution of the virus, medical advances in covid-19 treatments and preventative measures like improved ventilation and social distancing.
So far, the race between vaccinations and virus evolution is a dead heat. As of 17 January, 9.68 billion doses of covid-19 vaccines had been administered in a little over a year. This is a huge number, and has substantially brought down the fatality rate in high-income countries, but the United Nations estimates that there were 7.88 billion people on Earth in 2021. That means the vaccine doses so far represent slightly more than one per person.
In practice, there is enormous inequity. Many children worldwide haven’t been vaccinated and in low-income countries only 9.5 per cent of people have had even one dose.
For the original virus, and older variants like alpha and delta, two doses of vaccine gave sufficient protection. The implication was that almost 16 billion doses were needed to vaccinate everyone. Achieving that by the end of 2022 would be a challenge, but not an insurmountable one.
However, the omicron variant is a game changer: two doses of vaccine aren’t enough to give decent protection against infection or severe disease. “As things currently stand, you definitely do need three doses,” says Lance Turtle at the University of Liverpool, UK.
That means almost 24 billion doses of vaccine need to be delivered to give everyone on the planet three doses. To achieve this by the end of 2022, vaccines must be delivered this year at almost twice the average rate they were delivered in 2021.
That looks difficult, but the rate of vaccine delivery has accelerated over the past year. Currently, nearly 33 million doses are given every day. If that was sustained throughout 2022, an additional 12 billion doses would be delivered, for a total of 21.7 billion. In theory, it wouldn’t take a huge increase in the daily rate to get to 24 billion by the end of the year.
But in practice, delivering vaccines to lots of people in low-income countries is hard.
“The technological solution is only part of it – you’ve got to have all the steps from invention to manufacture to financing to the health systems to deliver it,” says Anne Johnson, president of the Academy of Medical Sciences in London. People in low-income countries often live in crowded, informal settlements where record-keeping is poor, or far from major cities in hard-to-access remote areas. “It’s a huge organisational challenge,” she says.
This has been compounded by high-income countries hoarding vaccine doses. Lower-income countries have struggled to obtain vaccines, and more doses have been given as boosters in high-income countries than have been given in total in all low-income countries.
A collaboration called COVAX has tried to send vaccines to low-income countries, but for much of 2021 it struggled to do this. So far, it has shipped 1 billion doses to 144 countries. It may get a boost from a vaccine called Corbevax, developed by Texas Children’s Hospital and licensed to Indian pharmaceutical firm Biological E. Corbevax is designed to be more easily made and stored, and is given patent-free to manufacturers.
Even three doses per person may not be enough to bring the pandemic under control. With omicron, the protection against symptomatic infection wanes within weeks of a third dose. Israel is already giving people over the age of 60 a fourth dose and other countries may follow suit. Vaccinating everyone on the planet every six months would be a vast undertaking, however.
Some form of regular vaccination is likely to be needed to keep the covid-19 death rate down. “For respiratory infections, we don’t get lifelong immunity that prevents us getting infected,” says Rustom Antia of Emory University in Atlanta, Georgia. If SARS-CoV-2 behaves like other human coronaviruses, “we need to forget about herd immunity”.
“I think it will be with us forever in the population, most likely, and I think we’ll need annual vaccines,” says Turtle.
That will include young children, says Pagel: “I imagine eventually it’ll be part of your childhood immunisation programme.”
Vaccinating children will be important, because we are unlikely to bring infection rates down if a substantial part of the population – especially one that mixes together in schools on a daily basis – is unprotected.
After initially focusing solely on vaccinating adults, the UK government announced in September 2021 that it would offer vaccines to 12-to-15-year-olds. But it hasn’t widely offered vaccines to younger children.
This is in contrast to other countries including the US, which has been vaccinating 5-to-11-year-olds after the Food and Drug Administration authorised the use of the Pfizer/BioNTech vaccine for that age group in October 2021. Ireland also recently announced it would offer that vaccine to 5-to-11-year-olds.
But in the UK, while the Pfizer/BioNTech vaccine for 5-to-11-year-olds has been approved, the Joint Committee on Vaccination and Immunisation has only recommended that the vaccine be offered to children in this age group if they “are in a clinical risk group or who are a household contact of someone (of any age) who is immunosuppressed”.
The roll-out of vaccines to children in other countries follows extensive and ongoing clinical trials. In a November statement, the WHO said the authorised vaccines were “safe and effective” for children. The WHO also noted that children who can’t attend school, either because it is closed or because they are ill with covid-19, are missing out on education, and in some cases may struggle to go back.
Meanwhile, the vaccines are being tested, in smaller doses, in even younger children. Pfizer and BioNTech have an ongoing trial in children aged 6 months to 5 years. However, in December, the firms announced that they were adding a third dose to the regimen, after a second dose didn’t provide enough protection. As a consequence, no results are available yet.
Similarly, Moderna says it expects data on its vaccine in 2-to-5-year-olds by March. If the results are satisfactory, the companies will seek approvals to deliver the vaccines.
An evolving virus
Even as governments run their vaccination programmes, the virus continues to evolve. It is hard to say what will happen next, because the virus has repeatedly confounded expectations. “I don’t think any of us imagined that 18 months down the line we’d be still here,” says Johnson.
In one respect, the omicron variant isn’t as bad as it might have been: it causes less severe illness than other variants such as delta. However, the next variant may be different. “You hear this said quite often that viruses adapt to their hosts and become less virulent,” says Turtle. “The evidence for that is not that great. In Ebola, in 2014, the opposite happened.”
“There’s no real selection pressure on this virus to become milder,” says Aris Katzourakis at the University of Oxford. That is because most of the spread happens in the early stages of an infection, before the person becomes ill enough to be bed-bound and thus unable to spread it. “If a virus hospitalises its host straight away, that might lead to selection pressure for a milder strain,” he says. But that isn’t the case here.
Instead, the lesson of omicron is that “there could be more surprises in store”, says Turtle. “Who knows how many other variants that could escape or be radically different and still infect humans are possible,” he says.
Better vaccines could make a real difference. Katzourakis says future ones could target more parts of the virus, rather than just the spike protein that enables it to enter cells. This would make it harder for the virus to evolve to escape them.
Some researchers are even aiming for a universal coronavirus vaccine, which would protect against all possible variants. But the work is in its early stages. A putative universal vaccine developed at the Walter Reed Army Institute of Research in Silver Spring, Maryland, has been tested in primates and is undergoing phase I trials to find out whether it is safe to give to humans. But more testing is needed, so a widespread roll-out is months away at best.
Even without such advances, simply giving people more vaccine doses makes it less likely that another game changer like omicron will emerge this year. As more people are immunised, fewer copies of the virus will circulate and its evolution will slow. “So far, none of the variants have arisen in countries with high vaccination rates,” says Pagel, suggesting that vaccination tempers the virus’s ability to transform itself.
Ultimately, ending the pandemic will take coordinated global action: something that has been sorely lacking so far.
On 3 January, Pagel, Katzourakis and their colleagues called for a global “vaccines-plus” plan. As well as vaccinating the world, they argue for a suite of measures, including high-quality face masks for indoor mixing, effective means of testing, tracing, isolating and supporting people who get infected, and better ventilation and filtration of indoor air.
“In the way Victorians went for clean water, sanitation, we have to go for clean air,” says Pagel. She emphasises that this offers multiple benefits. “There’s no individual liberty taken away that way, and it works against all kinds of airborne diseases.”
So far, no such global initiative is on the cards. Hence the statement given by Tedros Adhanom Ghebreyesus, director-general of the WHO, on 30 December: “As we enter the third year of this pandemic, I’m confident that this will be the year we end it – but only if we do it together.”
It is theoretically possible for the pandemic to end in 2022, but the logistical and sociopolitical challenges are immense. “I think it’s mathematically but not politically possible,” says Katzourakis.
The reality is that we have been “living with covid” for two years, and are likely to do so in some form for the rest of our lives. The crucial question is, how much of it will we live with? That will determine how many more people die or develop long covid, and how many more times countries will have to implement drastic restrictions after the emergence of new variants.
For some, the phrase “living with covid” has become a shorthand for “let’s not do anything else”. But without something like a global vaccines-plus plan, “we’re going to be in a race of chasing after variants for years to come”, says Katzourakis.
