Britain today recorded 114 more Covid-19 victims with the rolling average number of daily deaths now 10 per cent higher compared to last week amid accusations the government’s official numbers are too high.
Department of Health figures show 82 Britons are now succumbing to the life-threatening infection each day – up from the seven-day mean of 74 last Friday. More than 1,000 people were dying each day during the darkest days of the crisis in April.
Alarming statistics also reveal a similar jump in cases, with officials today confirming 687 more Britons had tested positive – taking the average to 609 infections. For comparison, the rate last Friday was 556.
Other data released today from the Office for National Statistics (ONS) said the coronavirus outbreak in England isn’t changing in size and 1,700 people are still catching the illness every day.
While SAGE today revealed Britain’s coronavirus outbreak is still shrinking by up to 5 per cent a day but warned the R rate could be above one in the South West of England and London. Scientists said the data showed ‘there is no indication the epidemic has gotten out of hand as a result of the easement’ of lockdown.
It comes as the Health Secretary today ordered Public Health England to review the way it counts deaths because of a ‘statistical flaw’ that means officials are ‘over-exaggerating’ the daily toll.
PHE counts people as victims if they die of any cause any time after testing positive for Covid-19 – even if they were hit by a bus months after beating the life-threatening infection, top academics revealed last night. The method is likely why the daily fatality tolls are not dropping quickly in England because survivors never truly recover from the disease as their deaths are blamed on the coronavirus – regardless of their real cause.
While separate ONS figures revealed coronavirus is no longer the leading cause of death in England and Wales but official figures show it was still the third most common way to die in June, behind only dementia and heart disease.
It comes after Boris Johnson today urged all workers to return to offices in August as he set out his timetable for life in the UK to return to normal by Christmas. In a Downing Street press conference, he revealed restrictions on the use of public transport in England are being dropped immediately with trips on the train and bus to no longer be viewed as the option of last resort.
In other coronavirus developments in Britain today:
- Security Minister James Brokenshire said the UK is at least ’95 per cent’ certain the Kremlin gave the green light for Russian cyber attacks designed to steal coronavirus vaccine research;
- Britain could already have herd immunity against Covid-19 because so many people have had similar illnesses in the past, an Oxford University study claimed;
- Half a million coronavirus tests made by Randox and used by thousands of Britons were recalled after spot checks revealed they were not sterile.
Dr Loke’s analysis shows that ‘all settings’ deaths (red bar) remain very high in England even as hospital deaths (blue bar) – which the Office for National Statistics says should make up two thirds of the total – have plummeted
COVID-19 WAS STILL THE THIRD MOST COMMON CAUSE OF DEATH IN JUNE
Covid-19 was still the third most common cause of death in England and Wales over June. Dementia and Alzheimer’s took the lead for the most frequent underlying cause of death followed by heart disease. The leading causes of death are shown per 100,000 of the population
Covid-19 was still the third most common cause of death in England and Wales in June, even though the darkest days of crisis are over.
One in 14 deaths were caused by the coronavirus in June – the same month Number 10 began to relax strict lockdown measures.
The disease was written on 2,525 death certificates, meaning 50,335 confirmed or suspected Covid-19 deaths have been recorded over the course of the pandemic.
But coronavirus deaths in June were significantly lower than they were in May, when the life-threatening infection accounted for a fifth of all fatalities.
And it’s the first time since March that the coronavirus was not the leading cause of death, according to the Office for National Statistics (ONS) data released today.
Dementia and Alzheimer’s took the lead for the most frequent underlying cause of death in June, accounting for 10 per cent of fatalities.
Department of Health figures released yesterday showed 130,000 tests were carried out or posted the day before. The number includes antibody tests for frontline NHS and care workers.
But bosses again refused to say how many people were tested, meaning the exact number of Brits who have been swabbed for the SARS-CoV-2 virus has been a mystery for a month — since May 22.
Health chiefs also reported 642 more cases of Covid-19 today. Government statistics show the official size of the UK’s outbreak now stands at 292,552 cases.
But the actual size of the outbreak, which began to spiral out of control in March, is estimated to be in the millions, based on antibody testing data.
It means the rolling average of daily cases dropped to 584 — 5 per cent higher than the 556 average cases figure recorded last Thursday.
The daily death data does not represent how many Covid-19 patients died within the last 24 hours — it is only how many fatalities have been reported and registered with the authorities.
The data does not always match updates provided by the home nations. Department of Health officials — who say the overall lab-confirmed death toll now stands at 45,119 — work off a different time cut-off, meaning daily updates from Scotland as well as Northern Ireland are always out of sync.
And the count announced by NHS England every afternoon — which only takes into account deaths in hospitals — does not match up with the DH figures because they work off a different recording system.
For instance, some deaths announced by NHS England bosses will have already been counted by the Department of Health, which records fatalities ‘as soon as they are available’.
More than 1,000 infected Brits died each day during the darkest days of the crisis in mid-April but the number of victims had been dropping by around 20 to 30 per cent week-on-week since the start of May.
NHS England today posted 16 deaths in hospitals across the country, including none in London for the second day in a row or the South West. One fatality was recorded in all settings in Wales but none were registered in either Scotland or Northern Ireland, according to official updates.
It comes as two leading experts who uncovered the flaw in the way PHE counts deaths today told MailOnline their ‘best guess’ was that more than 1,000 people have had their deaths wrongly recorded as caused by Covid-19.
Dr Yoon Loke, a pharmacologist at the University of East Anglia, warned that it is ‘not a good way of collecting data’, has had a significant impact in the past two months and is happening because PHE ‘chose a quick and easy technique’.
And the daily death tolls may not hit zero ‘for months to come’ because of a long tail of elderly people who beat Covid-19 but will die of other causes, Dr Loke added. He uncovered the flaw alongside Oxford University’s Professor Carl Heneghan.
BRITAIN’S OUTBREAK IS STILL SHRINKING BY 5% A DAY, SAGE SAYS
Britain’s coronavirus outbreak is still shrinking by up to 5 per cent a day, according to official data released today — but SAGE has warned the R rate could be above one in the South West of England and London.
The Government’s scientific advisory panel revealed the UK’s current growth rate — how the number of new cases is changing day-by-day — is between minus five and minus one per cent.
It is more confirmation the crisis is still petering out and suggests the reopening of pubs, restaurants, hairdressers and beauty salons on July 4, dubbed ‘Super Saturday’, has not triggered a resurgence yet.
But the figures show the UK’s outbreak is now be shrinking at a slightly slower speed because the growth rate has crept up from last week’s rate of minus 5 per cent to minus 2 per cent per day.
Scientists today said they were ‘cautiously optimistic’ about the data, which they say shows ‘there is no indication the epidemic has gotten out of hand as a result of the easement’ of lockdown.
But they warned Brits ‘must stay completely vigilant’ because a lag in the statistics means it is at least two weeks behind and it could take until next week for any spike to become visible.
Separate figures released by SAGE today shows the virus’s reproduction rate — the average number of people each Covid-19 patient infects — is still between 0.7 and 0.9 as a whole for the UK, meaning it hasn’t changed in two months.
But SAGE admitted the R could be as high as 1.1 in the South West of England, where Britons have been flocking for stay-cations to enjoy the coastline of Cornwall, Devon and Dorset, and in London, where pubs have been rammed with customers after reopening earlier this month.
For England as a whole, the R is slightly higher than the rest of the country, with the reproduction number hovering between 0.8 and 1. Keeping the rate below one is considered key because it means the outbreak is shrinking as not everyone who catches it passes it on.
Dr Loke said: ‘By this PHE definition, no-one with Covid in England is allowed to ever recover from their illness.’
Prime Minister Boris Johnson confirmed in a press conference today that the Health Secretary has ordered PHE to review the way it is counting people’s deaths.
It comes after a string of mistakes at PHE, including stopping testing and tracing at the peak of Britain’s outbreak. Tory MP David Davis this month told MailOnline the organisation had ‘made a complete mess’ of Covid-19 testing.
A Department of Health spokesperson said today: ‘The Health Secretary has asked Public Health England to conduct an urgent review into the reporting of deaths statistics, aimed at providing greater clarity on the number of fatalities related to Covid-19 as we move past the peak of the virus.’
The way PHE counts victims on a daily basis works by it combing through records of people who have tested positive for Covid-19 in the past to see if they have died. If they have, their death is automatically added to the coronavirus count.
It means that if, for example, somebody tested positive in April but recovered and was then hit by a bus in July, they would still be counted as a Covid-19 victim.
Dr Loke pointed out that unless PHE changes its system, all 292,000 people who have tested positive so far will be added to the Covid-19 death toll when they eventually die.
The Department of Health, which uses PHE’s data for its daily announcements, has so far counted 45,119 fatalities with 66 announced yesterday.
The ‘statistical flaw’ should not drastically affect the total number of deaths but means the ongoing death tolls appear worse than the reality.
The Office for National Statistics – which is not affected by the counting method – has confirmed at least 50,698 people have died in England and Wales up to July 3.
Public Health England admitted it is counting the deaths of anyone who tests positive for Covid-19, regardless of how long afterwards they died.
Dr Loke said: ‘It seems that PHE regularly looks for people on the NHS database who have ever tested positive, and simply checks to see if they are still alive or not.
‘PHE does not appear to consider how long ago the Covid-19 test result was, nor whether the person has been successfully treated in hospital and discharged to the community.
‘Anyone who has tested Covid-19 positive but subsequently died at a later date of any cause will be included on the PHE Covid-19 death figures… even if they had a heart attack or were run over by a bus three months later.’
The pharmacologist, who published his findings in a blog post last night, said the bizarre way of recording deaths is why there are such wide variations in daily figures.
Health Secretary Matt Hancock has called for an urgent review into the way deaths are being counted by Public Health England
On Monday July 6, for example, 16 deaths were recorded, while 152 were announced the next day on Tuesday the 7th.
WHAT ELSE HAS PUBLIC HEALTH ENGLAND COME UNDER FIRE FOR?
Public Health England has been in the firing line for a number of dubious decisions taken during the coronavirus pandemic.
STOPPING TEST & TRACE
When the first cases of coronavirus appeared in the UK, Government policy was to test everyone who had symptoms after returning from abroad and to trace people they had come into contact with.
However, on March 12, testing and contact tracing stopped completely. PHE no longer had the capacity to test the amount of people who were coming into the country infected with the virus after trips to Italy and France in half-term.
The decision has since been branded disastrous and a contributing factor to the UK’s devastating outbreak.
‘THEY WERE OVER-CONTROLLING’
Conservative MP David Davis told MailOnline this month that Public Health England had been over-controlling and made a mess of coronavirus testing.
The Tory MP said: ‘They made a complete mess of the testing arrangements; they were over-centralised, over-controlling and massively reduced our ability to test.’
He warned the decision – criticised heavily by top scientists at the time – then ‘handicapped’ later decisions and was ‘precisely the wrong thing to do’.
‘Before the winter crisis, the government has to reorganise this, whether that’s abolition or taking some of the powers away from them and giving them to someone else,’ he added.
OVERLOOKING LOCAL AUTHORITIES
Public Health England kept too much power over testing and contact tracing and should have delegated it to local authorities, one expert said.
Professor John Ashton, a former public health director, said Britain should have followed the example of Cuba where local teams went from house to house screening people for coronavirus.
He said: ‘The local public health level has been neglected. I think we’ve missed an opportunity because we should have made more use of primary care, local government and volunteers…
‘Instead what we did was a very top-down, London-centric approach.’
The Department of Health has blamed low numbers on Sundays and Mondays on a ‘weekend effect’ which means paperwork doesn’t get completed.
But academics are increasingly confused about why there are such wild variations, and why the number of deaths seems to remain so high.
And it appears to be simply that anyone who dies after being added to a register of people who have tested positive is classified as a victim.
It is currently impossible to know how many of the deaths announced by the Department of Health were not actually caused directly by Covid-19.
Dr Yoon Loke said the error has emerged because Public Health England chose a ‘quick and easy technique’
Dr Loke told MailOnline: ‘This is a very serious issue for public confidence.
‘When you go onto social media you will see hundreds of posts from rightly anxious people who are petrified at the seemingly relentless, unyielding daily death toll in England. The public are scared.
‘The public are asking questions about why England is doing so badly, when actually the truth is that the healthcare professionals in NHS are doing a great job in ensuring thousands of Covid survivors. The statistics here are misleading the public.
‘Because of this major flaw in the statistics, and the fact that tens of thousands of older people are being monitored, there is going to be a very very long tail of daily deaths.
‘The death toll will go down exceedingly slowly. It’s certainly not going to get to zero for months to come yet, because older people who have recovered from Covid-19 will unfortunately still succumb to other illnesses.’
Professor Carl Heneghan and Dr Jason Oke, Oxford University researchers who published Dr Loke’s work on their website, said that officials also seem to be spreading out historical deaths and just adding them on to ones that are happening now.
The pair pointed out the death counts from NHS England, which are accurate around three days after the date in question, are too low to match counts from PHE.
According to the Office for National Statistics, hospital fatalities now make up around 60 per cent of all deaths that happen on any given day.
On June 30, NHS England recorded 27 fatalities. If this was 60 per cent of all deaths that happened on that day the total number would be 45.
But the Department of Health, using PHE’s data, announced 115 more deaths on that day.
Dr Loke now suggests these massively inflated numbers are because PHE is counting people who died outside of hospital but didn’t die of coronavirus at all.
He wrote: ‘PHE data confirm that more than 125,000 patients have been admitted to NHS hospitals for Covid-19, the majority being successfully treated and discharged.
‘There are now less than 1,900 patients in hospital. So, roughly 80,000 recovered patients in the community will continue being monitored by PHE for the daily death statistics.
‘More and more people (who are mainly in the older age group) are being discharged to the community, but they clearly may die of other illnesses.’
Dr Loke said it would be a ‘reasonable approach’ to set a three-week limit on blaming someone’s death on coronavirus unless they were in hospital.
Public Health England told MailOnline that the World Health Organization has not defined a time limit for counting a death as caused by Covid-19, and said it ‘continues to keep this under review’.
It admitted that a coronavirus death is a death that happens to anyone who has previously tested positive, regardless of how long ago the test happened.
It said the ‘vast majority’ of Covid-19 deaths are correctly identified.
Dr Loke added: ‘This statistical flaw arose because PHE chose a quick and easy technique.
‘Their statistical method is reasonably accurate at the beginning of the pandemic, when there were not yet many people in the community who had survived Covid.
‘However, PHE did not – and have not yet – realised that glaring inaccuracies arise when tens of thousands of frail older people are discharged from hospital, and these Covid survivors unfortunately die from other, non-Covid related causes.
‘Like most things that are a quick fix, the monitoring system eventually churns out gibberish, and needs a thorough overhaul so that a lasting solution is implemented.’
Dr Susan Hopkins, Public Health England’s incident director, said: ‘Although it may seem straightforward, there is no WHO agreed method of counting deaths from Covid-19.
‘In England, we count all those that have died who had a positive Covid-19 test at any point, to ensure our data is as complete as possible.
‘We must remember that this is a new and emerging infection and there is increasing evidence of long term health problems for some of those affected. Whilst this knowledge is growing, now is the right time to review how deaths are calculated.’
CORONAVIRUS OUTBREAK IN ENGLAND IS UNCHANGING, DATA SHOWS
The coronavirus outbreak in England isn’t changing in size and 1,700 people are still catching the illness every day, according to the Office for National Statistics.
Estimates based on population testing suggest one in every 2,300 people is now carrying Covid-19 – a total of 24,000 people or 0.04 per cent of the population.
This is a slight rise from the 0.03 per cent (14,000) estimated last week but both are within a possible range, showing any change is not significant.
The number of people catching the virus each day – 1,700 – has not changed in a week, however, and the ONS said the outbreak has ‘levelled off’.
Separate studies by King’s College London and Public Health England that estimate new cases suggest the range is somewhere between 2,100 and 3,300 – higher than that found by the ONS.
ONS data is considered to be some of the most accurate available – this week’s update was based on the results of 112,776 swab tests taken over six weeks, of which 39 were positive.
Separate antibody testing by the ONS – looking at people’s blood for signs of past infection – suggests that 2.8million people, or 6.3 per cent of people in England, have had Covid-19 already.
The ONS said it has today changed the way it counts data and is following trends over a six-week period rather than a two-week period. As a result it advises against comparing the new estimates to old ones.
Britain could ALREADY have herd immunity against the coronavirus because so many people have had similar illnesses in the past, study claims
Britain could already have herd immunity against Covid-19 because so many people have had similar illnesses in the past, a study claims.
Experts have noticed the infection looks extremely similar to other, milder strains of coronaviruses which cause coughs and colds and circulate regularly.
Brits who have had these in the past may have some level of ‘cross-protection’, they suggest, which means they aren’t seriously harmed by Covid-19.
While it remains unlikely that people will be totally protected from any infection at all, ‘background’ immunity could make their illness less severe and death less likely.
Theories that even exposure to common colds may protect people from the coronavirus have been floating around for months and raise hopes for a milder second wave.
Combined with the fact millions of people have been infected in the pandemic’s first wave, it may mean the UK is already protected against another deadly surge.
The concept of herd immunity – in which so many people are immune to a virus that it cannot spread – is controversial because there is no scientific proof that people who have had Covid-19 once can’t get it again.
Scientists have claimed, however, that if immunity does develop, the proportion of people who need to have had it could be as low as 20 or even 10 per cent.
And Britain may already be reaching this level, the Oxford University paper said, adding: ‘[Immunity] measures of 10-20 per cent are entirely compatible with local levels of immunity having approached or even exceeded the [herd immunity threshold], in which case the risk and scale of resurgence is lower than currently perceived.’
Scientists say if a vaccine was developed it would need 60-70 per cent coverage to work — but this threshold could be significantly lower for natural immunity because the most at-risk people will always be the first to get exposed to the virus and, if it can’t infect them, it can’t spread through them to the less at-risk groups
WHAT IS HERD IMMUNITY?
Herd immunity is a situation in which a population of people is protected from a disease because so many of them are unaffected by it – because they’ve already had it or have been vaccinated – that it cannot spread.
To cause an outbreak a disease-causing bacteria or virus must have a continuous supply of potential victims who are not immune to it.
Immunity is when your body knows exactly how to fight off a certain type of infection because it has encountered it before, either by having the illness in the past or through a vaccine.
When a virus or bacteria enters the body the immune system creates substances called antibodies, which are designed to destroy one specific type of bug.
When these have been created once, some of them remain in the body and the body also remembers how to make them again. This provides long-term protection, or immunity, against an illness.
If nobody is immune to an illness – as was the case at the beginning of the coronavirus outbreak – it can spread like wildfire.
However, if, for example, half of people have developed immunity – from a past infection or a vaccine – there are only half as many people the illness can spread to.
As more and more people become immune the bug finds it harder and harder to spread until its pool of victims becomes so small it can no longer spread at all.
The threshold for herd immunity is different for various illnesses, depending on how contagious they are – for measles, around 95 per cent of people must be vaccinated to it spreading.
For polio, which is less contagious, the threshold is about 80-85 per cent, according to the Oxford Vaccine Group.
A study by Oxford University said the threshold needed to achieve herd immunity could be lower than expected – scientists had thought it would be around 60 per cent if a vaccine was used – because coronaviruses are common.
There are four other types of coronavirus known to infect humans regularly, which are named NL63, 229E, OC43, and HKU1.
The fifth, known as SARS-CoV-2, is the one that causes Covid-19.
If people have had these in the past, their bodies may have developed some immunity to coronaviruses, the Oxford researchers suggest.
Professor Suneptra Gupta and colleagues wrote: ‘It is widely believed that the herd immunity threshold (HIT) required to prevent a resurgence of SARS-CoV-2 is in excess of 50 per cent.
‘Here, we demonstrate HIT may be greatly reduced if a fraction of the population is unable to transmit the virus due to innate resistance or cross-protection from exposure to seasonal coronaviruses…
‘Significant reductions in expected mortality can also be observed in settings where a fraction of the population is resistant to infection.
‘These results help to explain the large degree of regional variation observed in seroprevalence [how many people have signs of immunity] and cumulative deaths and suggest that sufficient herd-immunity may already be in place to substantially mitigate a potential second wave.’
The way cross-protection might develop lies in the fact that coronaviruses all have similar structures – that is, they have spike-shaped proteins on the outside.
These spikes may look similar to the body’s immune system and be recognised as a threat even if someone has not been infected with that particular one before.
When the body recognises a protein as a danger it can stoke the immune system into life and immediately send white blood cells and antibodies to destroy the viruses, thereby either preventing illness or making it less severe.
The body stores memories of how to fight viruses it has seen in the past and, if it encounters one that looks a lot like another one it has attacked, it may attack that more quickly than usual, too.
Immune cells are highly specific and only attack the bugs they are designed to, but if coronaviruses are extremely similar there is a chance that immunity developed to one virus may be compatible with another.
CHILDREN ‘MAY BE PROTECTED FROM COVID-19 BECAUSE THEY GET SO MANY COLDS’
Children may be better protected against coronavirus because they get so many colds, some scientists believe.
There are four coronaviruses known to cause coughs and colds, with adults averaging between two to four colds a year.
But children are believed to attract up to 12 colds a year, and scientists say this could provide youngsters with a resistance to the virus that adults lack.
Professor Sir John Bell, a medicine professor at Oxford University, told the House of Lords Science and Technology Select Commitee: ‘How you respond may be due to the state of your existing immunity coronaviruses generally.
‘There is an interesting speculation at the moment, that many people in young or middle age groups may have T-cells that can already see coronaviruses.
‘It may well be able to provide some protection against this pathogen when it arrives.’
Professor Adrian Hayday added: ‘All adults past a certain age – 30 to 35 – eventually have no thymus so their T-cells work by looking at whether they have seen something before, whereas children are very good at seeing things that are unknown.
‘The issue may be that children are able to see this as something fresh.’
Coronaviruses are thought to cause up to 30 per cent of all colds but it is not known specifically how many are caused by the betacoronavirus types, which also cause severe chest infections in the oldest and youngest patients.
While this might not stop infection completely, the fast immune response could make the illness less severe and make it more likely that people will survive.
Research from scientists in Germany last month found that 81 per cent of people who had never even had the coronavirus produced some kind of immune response to it – which they put down to infection with common colds.
Researchers at the University Hospital Tübingen, who studied the immune reactions of 365 people, wrote: ‘Similarity to common cold human coronaviruses provided a functional basis for… immunity in SARS-CoV-2 infection’.
And Professor John Bell, another researcher at Oxford, recently said a significant number of people may have ‘background immunity’ to Covid-19.
He explained to MPs on the Science and Technology Committee that people were showing signs of a type of immunity called T cell immunity – T cells are ones that trigger the production of antibodies, which fight viruses.
Professor Bell said: ‘What seems clear is you do have cross-reaction from T-cells that are activated by standard endemic coronaviruses,’ The Telegraph reported.
‘I think they are present in quite a significant number of people.
‘So there is probably background T-cell immunity in people before they see the coronavirus, and that may be relevant that many people get a pretty asymptomatic disease.’
The Oxford team’s latest study – which did not involve Professor Bell – has not been published in a journal but on the website medRxiv without being reviewed by independent scientists.
In Britain’s first wave of the coronavirus pandemic, there have been almost 300,000 confirmed infections and 45,000 deaths.
Separate data suggests there have likely been more than 3.5million infections – most of them untested – and more than 60,000 fatalities.
Britain as a whole is not close to a high level of herd immunity, with Government testing surveys suggesting between five and six per cent of the population have had Covid-19 so far – about three million people.
London, however, has a much higher past infection rate at an estimated 17.5 per cent, so could be approaching a low level of protection.
THE MYSTERY OF COVID-19 IMMUNITY
Scientists still do not know for sure whether people can catch Covid-19 more than once or if they become immune after their first infection.
With some illnesses such as chickenpox, the body can remember exactly how to destroy it and becomes able to fend it off before symptoms start if it gets back into the body.
But it is so far unclear if people who have had coronavirus can get it again.
Tests have shown that many people who recover have antibodies – which can produce future immunity – but it is not known whether there are enough of them.
One doctor, Professor Karol Sikora, said he had found that only 10 per cent of people known to have had Covid-19 actually developed antibodies.
This means it is hard to measure whether they could fight it off immediately if infected again.
Another study, by the University of Melbourne, found that all patients in a group of 41 developed antibodies but, on average, they were only able to fend off 14.1 per cent of viruses if they were exposed a second time.
Research into other similar coronaviruses, which also infect humans but usually only cause mild illnesses, found that people did tend to develop protective immunity but their antibody levels dropped off within months and they could get reinfected again after around six months.
However, antibodies are only one type of substance that can produce immunity.
Others, including white blood cells called T cells and B cells, can also help the body to fight off disease but are more difficult to discover using currently available tests.
The Melbourne study found signs of elevated numbers of coronavirus-specific B cells and T cells in recovered patients, suggesting those types of immunity may be stronger than antibodies.
They called for more research on the subject.
A promising study done on monkeys found that they were unable to catch Covid-19 a second time after recovering from it, which led scientists to believe the same may apply to humans.
The rhesus monkeys were deliberately reinfected by scientists in China to test how their bodies reacted.
Because the coronavirus has only been known to scientists for seven months there has not been enough time to study whether people develop long-term immunity.
But, so far, cases of people getting infected more than once have not been numerous nor convincing.
The NHS is now preparing for a second wave of the disease but experts say they do not expect another one to be quite as devastating.
Future outbreaks will likely be confined to local areas and be able to be controlled with local lockdowns, they suggest.
While scientists around the world are racing to try and create a vaccine for the coronavirus, herd immunity may be vital as a long-term solution to the disease.
Sir Patrick Vallance, the UK’s chief scientific adviser, said yesterday: ‘It’s important to recognise that the chances of having a totally sterilising vaccine, i.e. one that 100 per cent protects you from this, I think, are low.
‘Much more likely that you have a vaccine that reduces the severity of illness and reduces spread a bit. I think that’s the more likely outcome on vaccines.’
Natural herd immunity – if lasting immunity develops from infection – can arise from the virus spreading through a large part of the population.
Immunity from a vaccine was expected to have to include at least 60 per cent of the population to effectively stop the virus from spreading.
But developing it through natural infection, meaning that the people most likely to spread the disease would get it first, may dramatically reduce that threshold.
A recent study claimed it could work to some extent if only one or two out of 10 people have been infected naturally and become immune to the disease.
They said higher estimates worked on the basis that immunity is given to everyone by a vaccine, but in reality the people who first get infected are likely to continue to be the ones most at risk, so if they develop immunity, the less-at-risk will also benefit.
These could include health workers, people who live in cities and those in people facing jobs like drivers, shop workers and schoolchildren and teachers, for example.
Immunity among the most socially active people, scientists say, could protect those who come into contact with fewer others.
The study led by Dr Gabriela Gomes, a mathematician at the Liverpool School of Tropical Medicine and the University of Strathclyde, said: ‘In idealized scenarios of vaccines delivered at random and individuals mixing at random, herd immunity thresholds are given by a simple formula which, in the case of SARS-CoV-2, suggests that 60-70 per cent of the population would need be immunized to halt spread considering estimates of R0 between 2.5 and 3.
‘A crucial caveat in exporting these calculations to immunization by natural infection is that natural infection does not occur at random.
‘Individuals who are more susceptible or more exposed are more prone to be infected and become immune, which lowers the threshold.
‘In our model, the herd immunity threshold declines sharply… and remains below 20 per cent for more variable populations.’
Another study has taken a similar line and suggested herd immunity could develop at around 43 per cent of the population getting infected.
Professor Frank Ball, Professor Tom Britton and Professor Pieter Trapman — three authors of the study from the universities of Nottingham and Stockholm — wrote in the journal Science: ‘Our application to Covid-19 indicates a reduction of herd immunity from 60 per cent… immunization down to 43 per cent in a structured population, but this should be interpreted as an illustration, rather than an exact value or even a best estimate.’
They said that immunity would be stronger in cities, large households and big workplaces.