Paddling pools are out, beer gardens are brimming. But a startling proportion of the population will be cooped up in their bedrooms having the strange experience of nursing a fever and sore throat in July as Covid infections continue to soar in the third major wave this year.
For most this will be an unpleasant inconvenience rather than a tragedy. But with a fourth wave expected in the autumn, a fifth potentially kicking off by Christmas and experts saying that Covid may never settle into a seasonal cycle, some are questioning whether this steady grind of illness is sustainable.
Seasonal flu has been a benchmark for Covid since the earliest phase of the pandemic and in the spring a threshold was crossed and Covid became less deadly than seasonal flu for all age groups. This was good news. However, the impact of an illness on society also depends on how many people are infected and how often.
Many had assumed that by this point we might be at least heading towards a more regular pattern of infection with Covid in which we would endure a few tough months during the winter and forget it for the rest of the year. Instead, the reverse appears to be occurring.
“The way that the pandemic has played out and is continuing to play out is unexpected,” said Dr Stephen Kissler, an epidemiologist at Harvard.
Kissler and colleagues published a highly influential paper in April 2020 that predicted that seasonal resurgences of Covid “could occur as far into the future as 2025”. For many in the scientific community, this was a coin-drop moment that provided a glimpse of what lay beyond the first few months of catastrophe and crisis – and sowed the seed of expectation that Covid would become seasonal.
“We’d expected strong seasonal wintertime patterns where you don’t see a lot outside those winter months,” said Kissler. This was because, with limited information to go on at the time, respiratory viruses have a natural advantage in the winter when people are cooped up indoors and when our immune systems are potentially less effective. And for many viruses, once a winter wave has passed, people remain immune for long enough to suppress infection until the following year.
Two years on, Kissler’s view has changed. “We’re in a different landscape now,” he said. “The fact we’re having such a rapid succession of variants – we seem to be racking them up at alarming speed – is the most surprising thing and that’s changed the way the waves look.”
“I would’ve thought it would have reached a steady state by now,” he said. “It seems the opposite is the case.”
Others have also been taken by surprise by this pattern. “It does look as if the successive waves are getting closer together,” Prof Peter Openshaw, an immunologist at Imperial College London, said. “They are actually becoming more frequent, with one piling in on top of the other.”
The change, Openshaw said, is that in the first year of the pandemic, new waves were driven by the emergence of more transmissible variants, such as Alpha and Delta, which spread infection more easily. Now, successive variants, including the latest BA.2.75 variant, nicknamed Centaurus, are being driven primarily by “immune escape” – the ability to infect people who have been vaccinated and infected, even fairly recently.
The Australian Health Protection Principal Committee advised this week that infections of BA.4/BA.5 variants could occur as early as 28 days after recovery from a previous Covid-19 infection.
“It almost seems as if the rate of replacement of new variants has accelerated,” he said. “There is a shift in what’s driving evolution.”
Each Covid wave no longer brings a shockingly high death toll, but it is still felt across the country. This week, school attendance in England fell to the lowest level since January, with nearly one in five secondary pupils absent and 8% of teachers off work.
Hospitals, already trying to process massive surgery backlogs, are coming under immense strain due to staff absences, with 26,874 NHS staff off work for Covid-related reasons last week.
Ambulance services are being pushed to the limit, with a paramedic describing them as “on the fringe of collapse” in a recent BBC report. And the already substantial numbers affected by long Covid are continuing to grow.
“In many settings, Covid is an inconvenience now, rather than a threat to life, but it continues to have a significant impact in healthcare” said Prof Tim Cook, a consultant in anaesthesia and intensive care medicine.
Essential infection control measures are an ongoing burden for hospitals and staff absences are piling pressure on the system even further. “It’s a fairly fragile eco-system,” Cook added. “You still have the issues of patients presenting later because primary healthcare is difficult to access, a degree of staff exhaustion, it remains a system under a lot of stress. From a healthcare perspective, the pandemic is not over.”
There is not a single, simple solution to curbing the steady tide of infection.
Vaccines have been an overwhelming triumph of the pandemic, but those in use have major limitations in managing this phase. They provide crucial protection against severe illness and death, but not against infection. And protection against mild illness wanes very quickly. This creates a zone of rapidly diminishing returns when it comes to boosting the young, healthy population.
“There’s clear recognition that what we’ve got now is not ideal,” said Adam Finn, a professor of paediatrics at the University of Bristol and a member of the UK’s Joint Committee on Vaccination and Immunisation, which announced on Friday that everyone aged 50 years and over would be offered a Covid booster in the autumn.
“We’ve got a tool that is really good at stopping the old folks from dying. We’ve more or less given up on the idea of mass immunisation to control the spread of infection. Vaccinating everyone every three months is just not feasible.”
Special cases could be made, he said, for vaccinating healthcare workers, for instance, in anticipation of a tough time in January. “Giving them all a vaccine in November would help,” he said.
This situation could improve as the next-generation vaccines become available. Major programmes are under way to develop variant-proof vaccines or even pan-coronavirus vaccines that would also work against other endemic coronaviruses, and some predict that these vaccines could produce more enduring immunity.
There are also efforts to develop a nasal vaccine, similar to the flu vaccine given to primary school children, that would be more likely to protect against infection and transmission – as well as illness.
Prof Danny Altmann, an immunologist at Imperial College London, is among those calling for governments to pursue these solutions with far greater intensity. “In early 2020, we had a real unity of purpose [on vaccines], which went terribly well,” he said. “After that we downed tools and lost interest. But it’s not job done, it’s job unfinished. We’re still in the heat of an arms race and we’re in a stage now we need to up our game.”
There are also the well-known lower-tech approaches to pandemic management. Germany is investing in improved ventilation systems in schools and public buildings, New Zealand announced this week that it would bring back free masks and Covid tests amid a growing Omicron wave and other countries continue to have stricter guidance on mask-wearing and self-isolation.
In the UK, there appears to be little enthusiasm for more active management of Covid, however. If we let nature follow its course, we will, according to Openshaw “reach some sort of equilibrium” with Covid. “But it may mean coexisting at a lower level of overall health.”
July 17, 2022 at 07:54PM Hannah Devlin Science correspondent