Thursday, September 16

Is Covid-19 on the run in the UK? | Coronavirus


JJohn Edmunds has been at the center of the outcome of the Covid-19 pandemic since the cases first appeared in January 2020. Member of Sage, the government’s scientific advisory group, and professor of epidemiology at the London School of Hygiene & Tropical Medicine has consistently warned ministers about the threats posed by the disease.

These risks have often been clear by their nature. But today, 18 months after the appearance of Covid-19, he believes that the nation is at a point of maximum uncertainty about the future of the pandemic.

“At any other point in the epidemic, it has been easier to foresee what might happen,” he told the Observer. “But at this point, I think it’s really difficult to understand what has happened and what is going to happen in the long term. There is great uncertainty about the disease at this time.

The fact that we are a year and a half in the pandemic and are still wrong about Covid-19 may seem surprising. After all, in that time, we have developed powerful vaccines to protect ourselves and have identified critically important drugs to treat patients. Science has done wonders.

However, researchers are still not sure how Covid-19 will progress in the UK in the coming months.

The statistics have certainly been surprising. First, the number of cases skyrocketed in early July. They then receded and began to fall, leaving statisticians and scientists scrambling to make sense of the fluctuating figures. To a large extent, a number of conflicting factors have been put forward to explain the Covid case numbers.

Has the opening of the company on July 19 had a significant impact? Did Euro 2020 drive the virus through England’s homes and pubs? Could the UK be getting closer to herd immunity? And what impact have school holidays had on the progression of the disease?

Unraveling these factors, as well as understanding the exact impact that vaccines have had on society, has now become a complex and urgent matter. “It will tell us how bad things will get when the partnership really opens in September and October and when winter approaches,” Edmunds said.

However, there is clear agreement on one factor. All the evidence indicates that vaccines now play a critical role in disease control. If the government had opened society entirely to an unprotected population, the daily death toll would now have skyrocketed into the thousands. But how far has our protection with vaccines gone?

It’s a crucial question, the answer to which will determine how severe the return of Covid-19 will be in the fall when schools reopen, the weather turns cold and people head indoors. A key factor is the degree to which the country has achieved herd immunity. In other words, have we reached the point where so many people have been infected or vaccinated and therefore possess some immunity to the disease, that viral transmission slows or even stops?

“You can run some very simple models to see if the case numbers we saw earlier this month are consistent with effective herd immunity,” said Professor Mark Woolhouse of the University of Edinburgh. And in my opinion, the answer is yes, it is. There are some important caveats, but the bottom line is that those numbers are consistent with the impact of herd immunity. “

Woolhouse pointed to a recent survey by the Office for National Statistics that showed that about 90% of adults in the UK he now possessed Covid antibodies, indicating that they might be capable of some kind of immune response to the infection. “That is a very large fraction and it may well be having an impact,” he said.

A packed sign outside a pub.
It is not yet clear whether crowds of euros in pubs increased infections. Photograph: Maureen McLean / REX / Shutterstock

Professor Martin Hibberd, also from the London School of Hygiene and Tropical Medicine, agreed that herd immunity was becoming a realistic prospect. “We’re getting close to herd immunity, but I don’t think we’re quite there yet,” he said.

But if we are getting closer to this goal, why was there such a rapid increase in cases in mid-July? What circumstances could have triggered this massive jump in infections in a nation that is supposed to be heading toward herd immunity? Scientists point to two key factors: euros and schools that are closed for holidays.

“If you look at herd immunity, you would expect it to peak at different times in different parts of the country, as there are different levels of immunity across the country,” Edmunds said. “But this is not what we saw: we saw a synchronous drop in cases across England. This suggests that an external factor was behind it, something that happened across the country at the same time. “

And the two most likely candidates, he said, are the schools that close and the “pingdemic” that occurred immediately after the euros. In other words, large gatherings of mostly male fans in pubs to watch England play football would have caused case numbers to jump in mid-July. This would have been followed by an increase in contacts who were asked to self-isolate after being linked to infected fans.

“This episode of self-isolation happened across the country at the same time and it appears to have reduced the cases,” Edmunds said. “But these would be expected to rise again, if it weren’t for the effect of school closings.

“Students no longer bring viruses home after contracting them in class. This is likely to help contain the cases now, and may do so over the summer. “

This point was supported by Woolhouse. “Now it’s been three and a half weeks since our peak in Scotland, and the numbers have yet to go up again. So, you know, I’m more confident that the underlying trend is in the right direction. “

Professor James Naismith, director of the Rosalind Franklin Institute in Oxford, also believes the near-term outlook is rosy. “It seems that the number of cases is stagnating, and you would expect them to drop a bit during the summer,” he said.

However, the problems will return in September when children go back to school, businesses open and people spend more time indoors.

“We will continue to have high levels of infection in the community. About one person in 65 is currently a carrier of the virus, and that means that virus levels are not going to drop significantly by September, ”Naismith said. “In these circumstances, the virus will have a good platform from which to start infecting those who are not protected when conditions make it more favorable for its spread.”

This point was supported by virologist Stephen Griffin of the University of Leeds. “I am concerned that even if the number of cases continues to decline, they will rise again strongly in September, when the schools return.”

One solution proposed by Naismith is to vaccinate 16 and 17 year olds across the UK. That would protect them from Covid-19 complications, which are worse than any vaccine complication they might encounter. It would also bring the population closer to the level it needs to achieve herd immunity.

“I think we are close to that immunity, but we will not be quite in the fall,” he added. “So we should think about vaccinating 16 and 17-year-olds or not. That would help us achieve more comprehensive protection against the virus. In any case, adolescents are perfectly capable of making their own decisions about the risks and benefits of vaccination. After all, 16-year-old Scots can vote. “

Two other puzzling issues hamper attempts to clarify the nation’s route out of the pandemic: new variants and a possible declining vaccine efficacy. Jeremy Farrar, Director of the Wellcome Trust, raises the danger posed by new lines of concern in Spike: the virus against the people, his new book on the pandemic. High infection rates increase the chances that a new variant will be cooked, he argues. “That is most likely why the worrisome variants have been traced to countries like the UK, South Africa and Brazil, which have had poorly controlled transmission.”

Hibberd echoes these fears. “Hopefully, the virus may not be able to mutate enough so that it can escape the immunity that vaccines or previous infections give it,” he told the Observer. “However, the appearance of a virus that evades immunity is a clear possibility. After all, it happens with other viruses, like the flu. We have to create new vaccines against influenza every year, and it mutates and comes back the following year slightly modified, and then we have to develop a new vaccine to combat it. “

Currently, scientists and pharmaceutical companies are working on vaccines to address some of the new variants that have appeared in the last year. For example, the Oxford vaccine team led by Dame Sarah Gilbert is working on one for the beta variant, first discovered in South Africa, which is considered to have the greatest potential to evade vaccines.

Healthcare worker with vial of Pfizer vaccine
The decreased effectiveness of the vaccine is also a cause for concern. Photograph: Christophe Archambault / AP

And then there is the question of the efficacy of the vaccine. Studies have shown that Covid-19 antibodies decrease over time in vaccinated people. This can limit people’s protection against the virus.

A study published last week indicated that the the effectiveness of the Pfizer vaccine decreases by an average of 6% every two months. Findings like these suggest that the government may need to establish a booster vaccination program for those over 50 to strengthen their protection during the winter.

These fears were highlighted last month by the Academy of Medical Sciences in its report, Covid-19: preparing for the future. “We’re going to go into this winter and start mixing again in ways that we didn’t do last year,” said Dame Anne Johnson, president of the academy. “Under those circumstances, we can expect to see a real increase in respiratory infections like the flu, against which we may have diminished immunity because we were not exposed last year.

Furthermore, the Office for National Statistics estimated, in its latest report, that a total of 856,200 people in England were infected with the Covid virus during the week ending July 24. That is a very large number.

“So whether the overall numbers go up or down slightly, the current situation is that we have a large amount of infection with a highly communicable variant. So the take-home message is clear: this pandemic is not yet gone.

“Exactly how it unfolds is a different matter. There are so many variables involved. In fact, the only thing that is clear is that the situation is very uncertain ”.


www.theguardian.com

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