Third Covid wave could last until AUTUMN with 100,000 daily cases – and ‘overshoot’ herd immunity
THE third wave of Covid-19 could last until AUTUMN with 100,000 cases a day, an expert has warned.
Carl Theodore Bergstrom, a biologist at the University of Washington, said there was a risk that a large wave of infection could “overshoot” herd immunity - prolonging the pandemic.
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Britain has seen cases soar in the past fortnight, driven by the highly transmissible Delta variant - but the vaccination programme has kept hospitalisations relatively low.
All legal Covid restrictions will end on July 19 - with face mask and social distancing mandates scrapped and mass events permitted.
The unlocking is expected to prompt a significant surge in cases, with Health Sec retarySajid Javid warning that infections could reach a peak of 100,000 a day as the country leaves lockdown.
Professor Adam Kucharski, an epidemiologist at the London School of Hygiene and Tropical Medicine, said scientists remained uncertain about the size of the wave and its duration.
He told the : “It's very difficult to predict, but the peak could easily get into the 50,000-100,000 daily cases range.
“It's also unlikely to be a brief, sharp peak, but rather a longer plateau over the summer into autumn.”
Prof Kucharski added that the wave could run for longer as, without restrictions, there would be no “single national intervention bringing transmission down at the same time”.
Herd immunity refers to the moment a pandemic begins to decline naturally because enough of the population has acquired immunity either through infection or vaccination.
But this does not signal the end an outbreak. Cases that occur after the threshold has been reached are called “overshoot”.
Experts warned that the UK could “overshoot” the herd immunity threshold - leading to unnecessary infections and hospitalisations.
In a widely shared Twitter thread, Prof Bergstrom wrote: “Implementing aggressive controls for even a short period around the herd immunity threshold reduces the overshoot and prevents many cases that would have occurred without control.
“For this reason, it’s a big mistake to open up right when you're reaching the herd immunity threshold but before the number of current cases – the momentum of the pandemic, so to speak – is low.
“This will generate a larger overshoot and lead to many preventable infections.”
It comes amid fears that restrictions could be reintroduced in the Autumn should hospitalisations continue to climb.
Vaccine passports are among the measures being considered by ministers as the country heads into a difficult winter, with the NHS expected to be under pressure.
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A note in the Government's Freedom Day blueprint reads: "However, it is possible that certification could provide a means of keeping events going and businesses open, if the country is facing a difficult situation in autumn or winter.
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"Any future implementation would involve consultation and appropriate parliamentary scrutiny."
Experts reportedly hope introducing vaccine passports over the autumn and winter months would drive jab rates up among younger generations, as well as stop a fourth wave.