Experts have said the UK could reach coronavirus herd immunity on Monday, the day Wales is due to ease restrictions further and allow all non-essential shops to reopen.
Modelling by researchers at University College London (UCL) has estimated that almost three-quarters of people (73.5%) will be immune to coronavirus by April 12.
The dynamic modelling, which says immunity will have been achieved by individuals by either having had the virus or by vaccination, is a contrast to the latest, more pessimistic, findings from the Scientific Advisory Group for Emergencies (Sage).
Modelling by Sage showed instead worrying details about a “highly likely” third wave of coronavirus later in the year. It forecasted that a full release from restrictions in June could trigger another wave of hospitalisations comparable to January’s.
However, while the Sage modelling did suggest a third wave is inevitable in early July, the size of the spike in cases depends on the effectiveness of vaccines, the speed at which restrictions are eased and the impact new variants have on transmission and illness.
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In contrast the UCL study astonished one of the authors, professor Karl Friston, of UCL, who said: “The herd immunity estimates surprised me.”
Prof Friston, a theoretical neuroscientist, said the modelling was averaged out over the four UK nations and the implications of the predictions are “best summarised in terms of the projections for unlocking”.
More detailed modelling at the level of local authorities for Wales can be seen in the local dashboard.
Prof Friston said the results were “unremarkable” given the fact that over 50% of adults have been vaccinated, around 42% of people have now been exposed to the virus and about 10% have pre-existing immunity.
“When factoring in the estimated efficacy of vaccination in terms of sterilising immunity, this – according to the model – means about 70% of the population are immune,” he said.
Prof Friston added that this level is “nearly at the herd immunity threshold” based on contact rates at the beginning of the pandemic and the estimated risk of transmission.
He told Gist Vile: “Crucially, the modelling predicts our responses to fluctuating levels of infection. A key observation is that the predicted unlocking is almost exactly the same as the government’s roadmap. In other words, a considered and prevalence dependent unlocking is endorsed by this modelling. Reaching herd immunity at this stage is just part of the process, which the four nations appear to be managing very well.
“The failure of the dynamic causal modelling to predict the third wave over Christmas was due to a failure to model fluctuations in transmission risk (e.g., due to viral mutations and seasonal variations). Now that we have data that allows the estimation of these fluctuations, we are much more confident about the long-term projections. Having said this, these projections should be read very much as a weather forecast and not taken too seriously.”
He is confident in the model outputs and added: “The short-term predictions of unlocking for the first wave were very accurate. I have also been impressed with the equivalent predictions of unlocking after the current wave. Having said this, short-term (weeks) predictions are generally more precise than long-term (months) predictions.”
The earlier Sage modelling, which was carried out by one of its sub groups, the respected Scientific Pandemic Influenza Group on Modelling, Operational (SPI-M-O), suggested that the resurgence in both hospitalisations and deaths would be “dominated by those that have received two doses of the vaccine”.
According to the latest data from Public Health Wales, infection rates and positivity levels continue to decrease giving hope to Wales’ path out of lockdown.
On April 12, all remaining pupils will be back in the classroom and all remaining non-essential shops and close contact services will be allowed to re-open.
In the second half of April restrictions will continue to be eased. Outdoor hospitality will reopen on April 26, and the extension of household bubbles will be allowed from May 10. You can read more here.
It is hoped that if case rates remain low, restrictions will be eased across Wales, aiming to move fully to alert level three by May 17. Providing Covid rates stay low, pubs and restaurants could reopen indoors in time for the Spring Bank Holiday at the end of May.