Experts and health professionals on what caused the recent drop in cases, living with Covid, and the uncontrolled spread of future variants.
First published in August 2021.
No virus found in train stations
The results of a study commissioned by Network Rail are out. The study looked for traces of COVID-19 by swabbing places train passengers touch regularly like escalator handrails, ticket machines, benches, and taking hour-long air samples on station concourses at four major railway stations. No traces of the virus were found anywhere. What conclusions can be drawn from the results of this study?
Professor Catherine Noakes, Professor of Environmental Engineering for Buildings, University of Leeds, member of SAGE:
“It is good news that sampling has not identified virus, and this confirms other studies that have also shown that there is not widespread contamination persisting in the environment.
“However, it is important to remember that sampling can only measure a very small part of the environment and it is a snapshot in time. This is particularly the case with air sampling, which will only be able to detect virus when an infected person is present at the time the sample is taken or very shortly before. The chances that the sample is taken at exactly the right moment and location to find virus in the air is therefore very small.
“Virus in the air can be removed quickly when ventilation is good. Ventilation rates on mainline trains are typically around eight air changes per hour, which means that once an infected person had left, the virus in the air would be reduced to undetectable levels in under 30 minutes. Station concourses are very large spaces which will also act to dilute any virus in the air to low levels. Mask wearing on public transport is also likely to be beneficial in reducing environmental contamination as this will significantly reduce the chance that virus is emitted into the air as well as stopping the larger droplets that land on surfaces.
“Transmission can happen anywhere where people interact together including homes, workplaces, social settings and on transport and so it is important that we continue to make sure we ventilate spaces well, wear masks when in crowded indoor settings, maintain good hand hygiene and stay home and get a test if you have any symptoms.”
Marylebone Station. | Wikimedia/Kwh1050
What caused the recent drop in cases?
According to data from the Zoe app (the world’s largest study of COVID-19), around 60,000 people are testing positive daily whilst government data showed a drop to under 30,000 positive tests in the past week. How can this be explained?
Professor Tim Spector, Professor of Genetic Epidemiology, Head of the Department of Twin Research and Genetic Epidemiology, King’s College London, Co-founder of the ZOE COVID Symptom Study app:
“This 60,000 figure is still a lot of people, it’s one in 84 people roughly who have at any point in time still some infection or symptoms of the condition.
“A sudden drop in people testing positive for the coronavirus in the government’s data is very suspicious.
“It’s dropped something like 30% in two days, which is pretty much unheard of in pandemics. And remember, this is happening without restrictions, without lockdowns, without some sudden event.
“To me, it looks a bit fishy.
“It looks as if there’s some other explanation for this other than suddenly the virus has given up.
“Looking at our own data, there’s a suggestion that we are seeing a reduction in the cases of the young and so they have been largely driving these figures for the last month or so, and that could be that less young people are getting tested.
“We are not able to easily get those government figures, but if the proportion of young people being tested is going down and older people is going up, that could explain this change.
“Keeping an open mind, we don’t know exactly what’s going on, just very suspicious of these dramatic changes and how they’ve occurred.”
The hypothesis is that the direct consequence of large gatherings of fans during the Euro 2020 competition would have been a jump in cases in mid-July, probably followed by a jump in contacts asked to self-isolate after being linked to infected fans, triggering the so-called “pingdemic”. Some experts think schools closing for the holidays would have thus started to hold cases down. What are the probabilities?
Professor John Edmunds, Professor of Epidemiology, London School of Hygiene and Tropical Medicine, Member of SAGE:
“At any other point of the epidemic, it has been easier to foresee what might happen. But at this point, I think it’s really hard to understand what has happened and what is going to happen in the long term. There is a huge amount of uncertainty about the disease at the moment.
“If you look at herd immunity, you would expect it to peak at different times in different parts of the country as there are differing levels of immunity across the country. But this is not what we saw: we saw a synchronous drop in cases right across England. This suggests an external factor was behind it – something that occurred across the country at the same time.”
“This bout of self-isolation occurred across the country at the same time, and it looks like it reduced cases. But these would be expected to go up again – if were not for the effect of school closures.
“Pupils are no longer bringing home viruses after picking them up in class. This is now probably helping to hold cases down, and may well do so over the summer.”
Castle Rock High School, Coalville. | Number 10
Living with Covid?
Libertarians out there, herd immunity scientists and UK ministers have been repeating that people should now just “live with Covid”. What are the risks?
Dr Zoë Hyde, Epidemiologist, Biostatistician, and Research Officer, University of Western Australia Medical School:
“Despite what some people want you to believe, it’s not possible to live with COVID-19.
“Each severe COVID-19 patient displaces about 20 patients with heart disease or cancer.
“Even fully vaccinated people will start to die from lack of healthcare if we abandon Zero COVID.
“We’ve been incredibly fortunate science has delivered highly effective vaccines. But they aren’t a silver bullet. We need to control transmission while we roll them out. If we continue on our current path, we risk rendering them ineffective.
“This doesn’t mean we should give up on vaccines and let everyone become infected. Infection-acquired immunity won’t last either if we allow huge amounts of transmission to continue. The solution is mass-production of vaccines for the world while continuing to control transmission.”
What about future variants?
PM Boris Johnson’s Covid-19 policy of shifting responsibility for managing the virus on to the individual is seen by most abroad as a strategy that will fail and ultimately create new, possibly more dangerous variants. What are the chances?
Dr Tom Frieden, Physician trained in Internal Medicine, Infectious Diseases, Public Health, and Epidemiology, Former Commissioner of Health of the City of New York:
“Delta emerged because of uncontrolled spread, and I worry that even more dangerous variants — including vaccine-resistant ones — could emerge if uncontrolled spread continues.”
Boris Johnson. | Number 10
— AUTHORS —
▫ PMP News reporting.
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[This piece was first published in PMP Magazine on 2 August 2021. | The author writes in a personal capacity.]
(Cover: Adobe Stock/freshidea. / Licensed under a Creative Commons Attribution-ShareAlike 4.0 International License.)