There are signs the UK could be heading for an autumn wave of Covid-19, and experts say the US may not be far behind.
A recent rise in Covid-19 cases in England does not appear to be driven by a new coronavirus variant, at least for now, although several are gaining strength in the US and across the pond.
“Usually what happens in the UK is reflected about a month later in the US. I think that’s what I kind of saw,” said Dr Tim Spector, professor of genetic epidemiology at Kings College London.
Spector leads the Zoe Health Study which uses an app to enable users in the UK and US report their daily symptoms. If they start feeling unwell, they take a home Covid-19 test and record those results. He says around 500,000 people are currently recording their symptoms each day to help track trends in the pandemic.
Spector says the study, which has been ongoing since the days of England’s first lockdown in 2020, has accurately captured the start of each wave, and its figures are around one to two weeks ahead of official statistics from the government.
After seeing a downward trend over the past few weeks, the Zoe study found a 30% increase in reported Covid-19 cases over the past week.
“Our current data clearly shows that this is the start of the next wave,” Spector said.
This increase was also reflected in official UK government data on Friday, although it was not as large as the increases reported by Zoe’s loggers.
National Health Service data showed that after falling for almost two months, the seven-day average of new cases in England and Wales rose 13% for the week ending September 17 compared to the previous week. The seven-day average of hospitalizations increased 17% in the week ending September 19 compared to the previous week.
The data matches what the models predicted would happen in the UK and US.
“They predicted that we would have a peak from June to July, then there would be a month where nothing happened in August, then it would level off in August and September, then start again in October. So it’s exactly what the modellers predicted,” Spector said.
In the United States, some models have predicted that Covid-19 cases would start to rise again in October and continue to rise through the winter. Experts hope that since most of the population now has some underlying immunity to the coronavirus, this wave would be less deadly than what we have seen in previous winters.
It is unclear what is driving the increase in the UK or if it will continue.
“These trends may continue for more than a week or two, or not,” said Kevin McConway, emeritus professor of applied statistics at the Open University in Milton Keynes, England.
Disaggregated by age, he says, there are clear increases in teenagers who are around college age and young adults, those between 25 and 34 years old.
“It wouldn’t be surprising if there was an increase in infection as people return from summer vacation and schools reopen,” McConway said in a statement to the nonprofit Science Media Center. “Even if it is, there is still no clear indication that this will continue. »
He’s not the only one who needs more data before calling it the start of a new wave.
“The first question is, how big is this increase? Is it, for example, the start of something, a new wave, or is it a temporary event because of all the gatherings around the Queen’s funeral and other events that have taken place? said Dr. Peter Hotez, who co-directs the Center for Vaccine Development at Texas Children’s Hospital in Houston.
A second important question will be whether the increase is due to a new variant.
“It’s the worst possible situation. Because historically when this situation happens in the UK it is mirrored within weeks in the US,” Hotez said. “It was true for the Alpha wave; this was the case of the Delta wave; this was the case with Omicron and its sub-variants.
This is where the United States could take a break this time around.
Instead of new variants, Christina Pagel, professor of operations research at University College London, thinks cases are rising in the UK due to a combination of decreased immunity and behavioral changes.
Many people in the UK are several months past their last Covid-19 recall or infection, and government statistics show that only 8% of adults aged 50 and over have received an Omicron-specific vaccine since the government launched its fall vaccination campaign in September. School and work have fully resumed after the summer vacation, and people are spending more time indoors as the temperature drops.
Immunity is also declining in the United States, and Americans have also been slow to get stronger. According to CDC data, only 35% of those for whom a booster is recommended got one.
Boosters updated in the US are slightly different from those in the UK. The UK uses vaccines that have been updated to combat the original version of Omicron, which is no longer circulating. US boosters have been updated to combat the BA.4 and BA.5 subvariants, which are currently causing infections here and abroad. It is unclear whether strain differences will have an effect on cases or disease severity.
There’s a mix of new variants – offshoots of BA.4 and BA.5 – waiting in the wings. They represent only a small proportion of the total number of cases, but several are increasing against BA.5, which still dominates transmission.
“It is very likely that these will accelerate the current increases and cause a substantial surge in October” in the UK, Pagel said in an email to CNN.
Other experts agree with this assessment.
“There is talk of a bunch of lines with worrying mutations, including BA.2.75, BQ.1.1, etc., but none of them are common enough in the UK at the moment to cause the change of cases,” Nathan Grubaugh, who studies the epidemiology of microbial diseases at the Yale School of Public Health, said in an email to CNN.
He says the mix of variants in the UK seems to be about the same as in the US, at least for now.
“We are currently seeing the rise of many respiratory viruses in the United States, so it is no exaggeration to think that a new COVID wave (or ripple) will arrive soon,” he wrote.