Scientists say as many as 20,000 people still catch coronavirus every day in Britain.
Trying to start contact tracing when the disease is still spreading so quickly would be “impossible” and there is always a “big problem” in nursing homes.
Professor John Edmunds, of the London School of Hygiene & Tropical Medicine, told MEPs today that the UK is still seeing “disappointing” deaths from COVID-19 and that the data is still not not good enough to break out of the lock.
There are also questions about the rate of reproduction of the virus – known as the R value – and how it varies across the country.
Foreign Minister Dominic Raab said at today’s briefing in Downing Street that he would be between 0.5 and 0.9 nationally.
Professor Edmunds put it between 0.75 and 1 and said it had increased in the past two weeks due to worsening epidemics in nursing homes across the country.
If the number exceeds 1, the epidemic will start to spread again and could become uncontrollable again.
Government statistics have revealed that an additional 5,614 people were diagnosed with COVID-19 yesterday – 35,000 people tested positive last week.
And there are now 12,692 people hospitalized with the coronavirus, which is a drop of 16% from last week, but shows that the disease is still widespread in England and Wales.
If Professor Edmunds’ prediction of 20,000 a day is correct, it could raise concerns about the government’s plans to start easing the foreclosure measures next week.
Yesterday, 5,614 people were officially diagnosed with COVID-19 and 35,000 cases were confirmed in the past seven days. But scientists say the real number could actually be more than 20,000 a day, four times more
Number of people hospitalized with COVID-19 has decreased by 16% over the past week to 12,692 – NHS now plans to slowly return to normal
Speaking to MEPs at a meeting of the Science and Technology Committee today, Professor Edmunds said: “The incidence must go down directly so that the search for contacts is really feasible, in order to be able to trace all these contacts for these individual cases.
“If we lower the incidence, I think contact tracing will play a role. I don’t think it’s enough to … I don’t want to rely on that alone.
“So I think we will need other measures of social distance. “
If the number of people infected each day remained at 20,000, the country could expect to see 100 deaths per day, assuming a death rate of 0.5%, which has been suggested by statistics from other country.
Tracing contracts could be impossible at this level of transmission because the government plans to employ around 18,000 contact tracers to locate people close to infected patients.
Officials will not be able to execute their “test, follow-up, tracing” plan until the number of new patients is kept under control.
The Imperial College COVID-19 response team, which advised the government, estimated in March that the global average coronavirus R0 was 3.87. When social distancing and locking took effect, that number has now dropped below 1, potentially as low as 0.5, which means that the virus will naturally disappear if this continues.
Leading German institute of disease says closely monitored R rate has dropped from 0.71 to 0.65, which means the epidemic is slowing down as it lifts lock restrictions and reopens schools
WHAT IS R0?
Each infectious disease is given a reproduction number, known as R0 – pronounced “R naught”.
This is a value that represents the average number of people that a sick person will infect.
WHAT IS R0 FOR COVID-19?
The R0 value of SARS-CoV-2, the virus that causes COVID-19, was estimated by the COVID-19 response team at Imperial College at 2.4 in the United Kingdom before the lockout started.
But some experts analyzing epidemics around the world have estimated that it could be closer to the 6.6 mark.
Estimates of R0 vary as the actual size of the pandemic remains a mystery and the speed of spread of the virus depends on the environment.
It will spread faster in a densely populated city where people travel on the subway than in a rural community where people drive everywhere.
HOW DOES IT COMPARE WITH OTHER VIRUSES?
It is thought to be at least three times more contagious than the coronavirus that causes MERS (0.3 – 0.8).
Measles is one of the most contagious infectious diseases and has an R0 value of 12 to 18 if it is not controlled. Widespread vaccination keeps it suppressed in most developed countries.
It is estimated that the R0 of chickenpox is between 10 and 12, while the seasonal flu has a value of around 1.5.
WHY IS IT IMPORTANT TO HAVE A LOW R0?
The higher the R0 value, the more difficult it is for health officials to control the spread of the disease.
A number less than one means that the epidemic will run out of steam and be forced to end.
In fact, the infectious disease will quickly miss new victims to strike.
HOW DOES LOCKING REDUCE R0?
The UK’s draconian lockdown, imposed on March 23, has slowed the coronavirus crisis in Britain, according to studies.
Last month, scientists from the London School of Hygiene and Tropical Medicine analyzed the virus in the United Kingdom.
They estimate that each infected patient now only transmits COVID-19 to 0.62 others, compared to 2.6.
The team said the virus had trouble spreading because people had less contact with others.
They used a survey of 1,300 people who were asked to list the human contacts they had in the past 24 hours.
This was compared to a similar survey done in 2005 to give an idea of how it had changed due to the foreclosure.
In addition to the decline in the number of people infected, the rate of transmission must also remain low thanks to social distancing and blocking measures, according to experts.
This is called the R value of the virus and indicates the average number of people to whom each infected person transmits the disease.
Prime Minister Boris Johnson last week placed the R – and the task of keeping it below 1 and preventing a further outbreak of infections – at the heart of the battle against the virus in Britain.
It was thought to be just below 4 at the start of the creeping epidemic in the UK, but Professor Edmunds now predicts that it is between 0.75 and 1, which means that if it can be sustained below 1, the epidemic will run out.
The chief statistician of the Office for National Statistics said in today’s briefing at Downing Street that R and the number of infectious people must go down together.
Professor Sir Ian Diamond said he “would not object” to the estimate that the R had increased in recent weeks.
He said: “It is important to recognize that the R number itself is only relevant if you also look at the prevalence context.
“I think we need to look at the two together to understand where we are … we certainly need to control the epidemic in nursing homes and hospitals. “
He said if the R was 1, the number of cases would stabilize because not more than one person would get the virus at the same time, but the number would not decrease either.
Dominic Raab added that “overall, the R is falling” and said that controlling infection rates in hospitals and nursing homes is now the government’s “priority”.
Although the rate of R is high in hospitals and nursing homes, which are high risk areas, it is considered to be very low in the community because people no longer have regular contact with others.
Professor Edmunds told the scientific committee that a few weeks ago he would have said that the R in the community was between 0.6 and 0.8.
But due to higher infection rates in medical facilities, he said, the overall estimate is now close to 1.
“This is a big problem we have in hospitals and nursing homes,” he said.
“I think what has happened is that the epidemic in the community is declining and that the epidemic is now concentrated in these settings. “
And Professor Edmunds added, “Our data is really not good enough to give us certainty about what the number of reproductions really is in hospitals and it is probably variable from one hospital to another, and the care homes are even worse. “
Professor Diamond said it is important to look at excess mortality during the coronavirus epidemic.
He added: “When we normally look at excessive deaths, we find the highest excessive deaths in the middle of winter, at the heart of what is often called flu season.
“Seeing them in the middle of a sunny April is sobering. “
Professor Edmunds’ comments come after a study by the University of East Anglia suggested that all measures of social distancing were not equal when it came to reducing coronavirus infections.
The document, which studied data and restrictions in 30 countries around the world, suggested that a complete lockdown may not be necessary.
One of the scientists involved in the research, Dr. Julii Brainard, said that he had found clear distinctions between the most effective measures.
“We found that three of the controls were particularly effective and the other two were not,” she told BBC Radio 4 this morning.
“It hurts me to say this because I have children I would like to take back into education, but closing schools was the most effective measure, followed by mass rallies.
” [This was] followed by what has been defined … like initial business closings. So that was the time when, in the UK for example, they closed gymnasiums and clubs.
“The measure of home support has surprisingly little additional effect, and additional business closings. “
Charts provided by researchers at the University of East Anglia compare how separate lockouts have affected their “risk ratio” – an algorithm that predicts the likelihood of the virus spreading. Gradients show that the risk has diminished over time after the ban on mass gatherings, the closure of schools and the closure of “first businesses”, including gymnasiums. Gradients that have shown less effect, or seemingly no effect on the risk ratio are shown, showing that the total number of business closings, staying at home and wearing masks does not appear to have any impact. on the risk of the virus spreading
The results of the study – based on data from 30 countries – also showed how the same measures worked to reduce the number of deaths
How the UK R number dropped when the lock was introduced and what it means for the emergence on the other side
Prime Minister Boris Johnson last week put detailed science at the heart of Britain’s coronavirus crisis and said the status of the lockout now depends on the number of times the virus reproduces – known as R.
Monitoring the number of new patients and the rate at which it is increasing or decreasing will be the best way for authorities to monitor the rate of spread of the virus, which in turn will guide the risks that the government believes should be taken by lifting the lock.
The data that presents Britain’s R-value will shape everyone’s life in the UK in the weeks and months to come, and MailOnline explains here how:
What is the R number?
Each infectious disease is assigned a reproduction number, which is known as R0 – pronounced “R naught” – or simply R.
It is a value that represents the number of people that a sick person will infect, on average, if the virus reproduces in its ideal conditions.
Most epidemiologists – scientists who track disease outbreaks – believe that the SARS-CoV-2 virus, which causes COVID-19, has an R value of about 3.
But some experts analyzing epidemics around the world have estimated that it could be closer to the 6.6 mark.
As an epidemic continues, R0 can be more precisely called Re or simply R, because other factors come into play to influence its ability to spread.
Estimates of COVID-19 R vary because the true size of the pandemic remains a mystery and the speed of spread of the virus depends on the environment.
As an epidemic progresses, R can simply be called R, which means the effective rate of infection – nothing assumes that no one in the population is protected, which becomes obsolete as more more people are recovering.
How does reproduction rate compare to other infections?
SARS-CoV-2 is three times more contagious than the coronavirus responsible for MERS (0.3 – 0.8).
Measles is one of the most contagious infectious diseases and has an R0 value between 12 and 18 if it is not controlled. Widespread vaccination keeps it suppressed in most developed countries.
The R0 of chickenpox is estimated to be between 10 and 12, but this is controlled in the UK by collective immunity. So many people catch it when they are children and become immune to reinfection that it cannot be spread among adults.
Seasonal flu has an R value of about 1.5 but it mutates so often – there are often one or more new strains each year – that people cannot develop full immunity against it. Recovering from a flu strain does not protect any of the others.
The Ebola virus has an R0 of between 1.4 and 1.8 – which is low, but has so far only spread to countries with poor health facilities and its extremely high mortality rate ( 50%) makes it a threat.
Mumps has an R0 between 10 and 12, which makes it very infectious, but the measles vaccine (MMR) protects most people in Britain from getting it.
The R0 for pertussis, medically known as pertussis, is estimated to be 5.5. The NHS urges mothers to get vaccinated against pertussis during pregnancy because they are able to transmit immunity to their babies naturally.
How is it calculated? And can scientists ever be sure of the number?
R is not a fixed number and scientists calculate it by studying the speed of spread of the virus in its perfect environment and also in society.
Although the biology of the virus and its spread – whether through cough or blood, for example – will have some influence, but human behavior is a more important factor.
Tracking the increase in the number of new cases and the rate at which the number of patients doubles are two of the best ways to estimate R, according to a lecturer in mathematical biology at the University of Bath and author of Maths of Life and death, Dr. Kit Yates.
He told MailOnline, “Most modelers will give uncertainty ranges with their estimates, suggesting that R could be as high as that or as low as that.
“R0 is not a fundamental property of the virus. This will change depending on the community through which the disease passes.
” [It] depends on three factors: communicability (the ease with which the disease passes between people); the infectious period (the longer it is, the more likely it is for an infectious person to transmit the disease); and the population affected by the disease.
“The more people and the more packed they are, the easier it will be for the disease to spread, so we can’t just take the R0 measured in one country and use it in another. “
Dr. Jennifer Cole, biological anthropologist at Royal Holloway University in London, said: “It is incredibly difficult to calculate [the R0] without doing it in retrospect.
She explained that detailed data can show how quickly the virus has spread, but it is more accurate when you look back in time, not right now.
“At the moment we don’t have exact numbers, but we have a rough idea,” added Dr. Cole.
“As long as you can say that the R0 is between one and two, or between three and four, this is broad enough to make the decisions you need on social distancing.
Did the UK R number drop when the lock was introduced?
The COVID-19 intervention team at Imperial College London estimated that the R0 value for coronavirus in the UK was 2.4 before the lockout started.
This meant that, before Prime Minister Boris Johnson ordered the national closure on March 23, 10 people infected with the virus would infect 24 others.
But scientists have since calculated that the rate has dropped below 1, which means that the crisis will end if the situation remains the same.
Researchers at the London School of Hygiene & Tropical Medicine said in an article published in early April that they thought the number was 0.62.
They interviewed 1,300 people about their whereabouts and contacts and to judge how many people they were likely to have infected if they carried the virus.
And England’s chief medical officer, Professor Chris Whitty, told MEPs at a science and technology committee meeting last week that the R was between 0.5 and 1.
His counterpart – chief scientific adviser Sir Patrick Vallance – also said the rate was similar, saying it is now between 0.6 and 0.9 in the UK.
Last night at the Downing Street press conference he suggested it was lower in London and added, “It is not exactly uniform across the country.”
If the number goes down, why are we still locked out?
Substantial reductions in the virus’s reproduction rate and the number of people infected are vital for the UK to even consider breaking the deadlock.
Number three on the government’s list of five criteria that must be met before the lockout ends is: “Reliable data to show that the infection rate is decreasing to manageable levels at all levels.”
While Sir Patrick and Professor Whitty say they believe the R is now less than one, the government probably lacks “reliable data” to prove it.
Until last week, COVID-19 tests had been limited to inpatients and medical personnel only, which meant that the true extent of the epidemic was unclear.
The tests are now deployed more widely with people who think they have the virus and also with more than 100,000 random people in the population.
A historic report released by Imperial College London on March 30 showed UK politicians how the reproductive rate of the virus could change as the country progressed in lockdown, using models of other countries which had earlier introduced strict social distancing measures (illustrated in series). This report came after a by the same team who estimated that up to half a million people could die if the government failed to act, which has been credited with persuading Boris Johnson to order the nation to stay home on March 23
Officials will now want to see the number of new cases diagnosed remain low even if they step up testing, which would show that the virus is on the way out. If the numbers continue to stay low and even go down for weeks, it would show that the disease is spreading slowly.
Because so few people have had the disease and developed immunity, it is essential that the number of people currently infected is kept as low as possible before the isolation is lifted, in order to prevent these patients from triggering another epidemic. .
Dr Yates of Bath said: “If the UK is easing social distance now, while most of the population is still sensitive, it runs the very real risk of a second wave.
“Right now, it is suggested that R0 could be around 0.7, which means that we have a bit of leeway to abandon full lockout.
ROSE DENMARK INFECTION RATES AFTER SCHOOL REOPENING
Danish authorities sent the children back to school two weeks ago and since then the rate of spread of coronaviruses has increased, according to officials.
The country experienced a relatively small outbreak, with only 9,356 officially diagnosed cases and 452 deaths.
As a result, it has undergone a shorter lockout and has already started to relax the restrictions.
However, the national infectious disease agency, Status for Smittetrykket I Danmark (SSI), has found that the virus’s reproduction rate has dropped to almost 1 – which could spark another epidemic – since schools reopened on 20 April.
It went from 0.6 to 0.9 during this period, reported The Local.
Research released earlier this week will prompt governments to think twice before reopening schools after revealing that children seem to be just as likely to catch and spread COVID-19 as adults.
In its status report, the SSI said: “There is no evidence that there is a real acceleration of the epidemic.”
“As long as we keep R0 below 1, the disease will continue to go away. The reason we keep the lock on for so long is because we want to bring the cases down to a very low level and the quickest way to do this is to keep R as low as possible.
“To some extent, the impact of different measures is quantifiable and the modellers use a series of different scenarios to advise the government on the best policy.
“But until we have the experience of lifting the various restrictions, we will not really know the effect on R. You can expect a lot of caution in the measures that the government begins to relax. Expect him to be conservative at the start.
Movements in government suggest that the lockdown of its current state should continue until June, after Scottish Prime Minister Nicola Sturgeon said yesterday that she thought it would be too soon to change when next week’s triennial review, to be held on May 7.
Professor Whitty, however, offered a glimmer of hope at a science and technology committee meeting last week when he said that the R being less than “gives a little leeway and ticking off some things while keeping it below 1 “. .
How will the 100,000 people test follow the R value after the lockout?
Sir Patrick Vallance, conseiller scientifique en chef de la Grande-Bretagne, a confirmé hier que les responsables iront de l’avant en utilisant des tests de population aléatoires et le nombre de cas officiels pour déterminer comment la valeur R change à l’avenir.
Il a déclaré lors du briefing de Downing Street: « Pour le moment, nous utilisons un R calculé en examinant toutes sortes de choses, y compris les contacts, la génomique, les données des ambulances, les admissions à l’hôpital, etc., pour calculer le R. »
Dans le cadre de son plan de test, de suivi et de suivi en trois points, au moins 25 000 personnes sont inscrites à un plan pour tester un échantillon de la population chaque mois pendant un an pour voir si elles sont actuellement atteintes du virus, le suivi au fil du temps.
L’Institut allemand Robert Koch publie les meilleures estimations quotidiennes du gouvernement sur le R0 du pays, montrant qu’il a chuté de près pendant le verrouillage d’avril
Dans une deuxième branche du projet de suivi, des personnes dans 1 000 ménages à travers le pays se soumettront à des analyses de sang mensuelles pour voir si elles sont immunisées contre le coronavirus d’être infectées par celui-ci dans le passé.
Le gouvernement testera également 100 000 personnes au hasard dans le cadre d’un test de dépistage sur écouvillon unique, pour avoir une idée de la proportion de la population actuellement infectée.
Public Health England effectue actuellement des tests d’anticorps dans son laboratoire de Porton Down pour se faire une idée du nombre de personnes qui ont eu le virus dans le passé et de la façon dont elles y ont développé une immunité, et jusqu’à 10 000 personnes seront renvoyées chez elles kits à ajouter à ces données.
Les premiers résultats de ces enquêtes nationales sont attendus au début du mois et aideront à rassembler une image du nombre de personnes infectées par le virus et de sa vitesse de propagation.
La London School of Hygiene & Tropical Medicine tente également d’estimer l’ampleur de la propagation du virus en interrogeant les gens sur leurs mouvements et leurs contacts sociaux au cours des derniers jours et semaines.
Il a estimé en avril que le R était passé de 2,6 à 0,62 au cours du premier mois du verrouillage britannique.
Les chefs de santé publieront-ils le numéro R tous les jours?
Les chefs de la santé n’ont pas encore révélé s’ils publieraient le numéro R chaque jour, bien que le Premier ministre ait mis le numéro au cœur de la bataille hier dans son discours.
Mais les ministres allemands – qui ont été largement félicités pour leur approche rigoureuse pour stopper l’épidémie – fournissent une mise à jour quotidienne.
Les rapports de situation publiés par l’Institut Robert Koch, le centre du pays pour le contrôle des maladies, montrent que le R0 est tombé en dessous de un le 15 avril.
Le nombre fluctue quotidiennement – il était de 0,9 mardi et de 0,75 hier, ce qui signifie que ce n’est peut-être pas une mesure fiable au jour le jour, mais pourrait être utile pour suivre au fil du temps.
Il serait utile de regarder le nombre R à la sortie du pays du verrouillage, car cela pourrait révéler exactement comment différentes mesures affectent le taux d’infection.
Le verrouillage s’est produit en une seule fois, mais sera levé pièce par pièce, ce qui signifie que le calcul de la façon dont chaque restriction affecte le nombre ne peut pas vraiment être connu jusqu’à ce qu’il soit supprimé.
Le Dr Robin Thompson, chercheur en épidémiologie mathématique à l’Université d’Oxford, a déclaré: « Un défi majeur consiste maintenant à identifier des mesures pouvant être assouplies qui n’ont que des impacts limités sur la valeur de R.
«L’une des raisons pour lesquelles cela est particulièrement difficile est que les interventions ont d’abord été introduites au Royaume-Uni à quelques jours d’intervalle. Par conséquent, il est difficile de démêler les effets relatifs de différentes interventions sur le nombre de reproducteurs. “