The Omicron variant has unleashed a tidal wave of Covid that is sweeping through countries at breakneck speed. In the UK, infections soared to unprecedented highs in recent weeks, but may finally have reached a peak. So what is in store on the other side of the wave?
When will cases fall?
Mass vaccination, boosters, and the spectacular infection rates seen in the Omicron wave are building high levels of population immunity that will drive infection rates down. The wave will peak at different times from place to place, with adherence to Plan B and shifts in people’s behaviour before and after Christmas all playing into the timing and speed at which infections fall. While the Office for National Statistics said infections were still rising in England last week, the wave may already have peaked in London.
Will Omicron fizzle out?
Not in the foreseeable future. The more likely scenario is that Omicron continues to circulate, with cases rising and falling in line with people’s mixing patterns and changes to measures that prevent transmission. When plan B is lifted and more people return to work, cases may well rise. But in the summer, as people spend more time outdoors, infections may fall again, then rise next winter. It will all come down to human behaviour. People may feel safer and socialise more as cases come down, sending infections up again. The virus won’t be wiped out because waning immunity means there will be a constant supply of people who are newly susceptible to the infection.
Will we see more hospitalisations?
Before the Omicron wave hit, about 5% of the UK population had no immunity to Covid, either through vaccination or past infection. Most of the severe disease caused by Omicron has occurred in this group of people. On the other side of the Omicron wave, there will be hardly anyone who hasn’t got some immunity from infection or vaccination and this should help to keep hospital admissions down.
But Omicron is still spreading fast, with nearly four million people infected in England alone last week. While infection rates appear to have stalled in the under-50s, they are rising in older, more vulnerable age groups. It still isn’t clear how severe Omicron can be in older people who had their boosters early and may now be seeing that immunity wane.
If cases keep falling, then population immunity and the arrival of new antiviral drugs that aim to slash hospitalisation rates, will help the UK emerge from the crisis. “We can definitely start planning for the future in which we are treating Covid like other diseases, but we aren’t there yet,” said Prof Rowland Kao, an infectious disease epidemiologist at the University of Edinburgh.
What about NHS Test and Trace?
With Omicron spreading fast and causing less severe disease, some researchers believe it is time to rethink how Test and Trace is done. “I think we are already at the point where PCR testing is a waste of resources, and contact tracing is probably a waste of resources too,” said Tim Colbourn, professor of global health systems and epidemiology at UCL. One option is to rely more on lateral flow tests and for people to message their close contacts whenever they test positive.
Other measures, such as pool testing samples from groups of people, and wastewater surveillance for the virus could flag new outbreaks, Prof Kao said, while some physical distancing and mask wearing in crowded places would continue to keep cases down. “We mustn’t forget that vulnerable groups will still likely remain more vulnerable,” Kao said.
Will there be more variants?
More Covid variants are inevitable and, like Omicron, they will have to evade immunity to some extent to spread widely. The key to reducing the risk of new variants is driving down case rates globally, but to date, vaccine hoarding and the widespread use of boosters in wealthier countries has left vast swathes of the world under-vaccinated. New variants may emerge from mutations in Omicron or other variants that are still in circulation.
Will the virus get milder as it evolves?
Not necessarily. The Alpha variant was more virulent than the original Covid virus that emerged from China, and the Delta variant was more virulent still. Omicron is somewhat milder, but there is no guarantee that future variants will be. The good news is that so far, even though several variants have developed resistance to antibodies, meaning they can spread among people who have immunity, so-called T cell defences have proved far more robust. The T cell defences are crucial for preventing hospitalisations and may continue to hold up well against future variants.
Will new drugs help?
That’s the hope. This year, doctors will have access to at least two new antiviral drugs, Pfizer’s paxlovid and Merck’s molnupiravir. Both are aimed at those most likely to become severely ill with Covid. If taken soon enough after infection, paxlovid and molnupiravir can reduce hospitalisations by 89% and 30% respectively. “At the beginning of the pandemic, Covid was by far the leading cause of death,” said Prof Colbourn. “This year we should be able to reduce the burden of Covid by 95% of what it was then, and it could fall out of the top 10 public health problems by May or June. The next test will be the next variant.”
