Coronavirus: WHO says 'no evidence' survivors have immunity - Money

There is no evidence to support the belief that people who have recovered from coronavirus will not catch it again, the World Health Organisation has said.

WHO chiefs have warned world leaders against investing too heavily in the tests to show if a person has already had the virus, because they do not guarantee immunity.

The UK Government has bought 3.5million serology tests, measuring antibodies in blood plasma, but they are not definitive in proving if someone has had the virus.

Many tests being developed are pin prick blood checks similar to widely used instant HIV tests and measure raised levels of the antibodies the body uses to fight the virus.

It comes as top health official said the coronavirus ‘immunity passports’ plan is doomed to fail after only 10 per cent of Italians have developed Covid-19 antibodies.

And a study by scientists at Stanford University in the US found as much as 4 per cent of California’s population may have already been infected with the virus.

A doctor shows a negative quick coronavirus test in a tent set up at a hospital in Caracas on Wednesday. Venezuela has rolled out the mass deployment of a rapid blood antibody test from China that checks for proteins that develop a week or more after someone is infected

A woman undergoes a serological test during the coronavirus lockdown in Milan on Tuesday

Britain and many countries had hoped antibody tests would allow those who can prove they have had the virus – and therefore thought to be immune – to return to work and stabilise the economy.

But Dr Mike Ryan, executive director of WHO’s emergencies programme, said there was limited evidence that coronavirus survivors were guaranteed future immunity to the disease.

This means those who have already had the virus could be at risk of being reinfected.

He added: ‘Nobody is sure whether someone with antibodies is fully protected against having the disease or being exposed again.

How scientists still don’t know if developing antibodies means lifelong immunity for coronavirus patients and whether tests will be accurate amid fears it will take years to create an accurate check

Does everyone who has survived coronavirus develop antibodies?

When someone is exposed to coronavirus, the body begins making proteins known as antibodies which fight the infection.

If these antibodies can successfully contain the virus and stop it spreading within the body, symptoms will normally start to reduce in patients.

The immune system will then completely destroy all the virus in someone’s body – leaving them with no long-term health effects if all goes well.

Everyone who develops Covid-19 will produce these antibodies, but small amounts of the virus may remain in the body for a few days after they feel fully recovered – hence the importance of self-isolation.

Sceintists are unclear whether developing antibodies means immunity will be lifelong – and they may only last an average of two years

Once someone has recovered from a viral infection, their body will retain cells known as lymphocytes in their system.

These effectively remember viruses the body has previously encountered, meaning it should quickly fight them off again.

This means your antibodies will probably stop the virus before it causes any noticeable symptoms – also known as ‘immunity’.

However, immunity can decrease over time for some viruses, which is why some people get revaccinated with ‘boosters’ which can prompt the immune system to make more antibodies.

The issue with Covid-19 is that because it is so new, scientists are currently unsure whether people who recover from the infection are immune to catching it again.

Furthermore, the World Health Organisation has warned there is limited evidence that coronavirus survivors were guaranteed future immunity to the disease.

Some early animal studies suggested that antibodies could block reinfection for at least two weeks.

But research on the new coronavirus’ closest relative – SARS – shows a patient generates antibodies that last an average of two years.

Tom Duszynski, an expert in epidemiology at Indiana University–Purdue University Indianapolis, said: ‘Doctors are finding antibodies in ill and recovered patients, and that indicates the development of immunity.

‘But the question remains how long that immunity will last. Other coronaviruses like SARS and MERS produce an immune response that will protect a person at least for a short time.

‘I would suspect the same is true of SARS-CoV-2 (the virus strain that causes Covid-19), but the research simply hasn’t been done yet to say so definitively.’

Once the test is developed, are they accurate enough to see people who have antibodies?

Guidelines from the US Centers for Disease Control and Prevention say that a person has recovered from Covid-19 when they have been fever-free without medication for three days in a row.

They must also show an improvement in other symptoms such as coughing and shortness of breath – as well as testing negative for the virus twice in two tests taken at least 24 hours apart.

As for the antibody test, government officials in the US and UK are yet to find one that is good enough for widespread use.

Columbia University expert Dr Susan Whittier has admitted it could take years to find a test which will be accurate enough, although scientists are trying to find a blood-based test within a few months.

The main issue is within identifying the exact antibodies produced by a body with a healthy immune system to fight the infection, which scientists are divided on.

This means antibody tests have been produced with various designs so far, some of which have failed to work with enough accuracy because they are not specific enough for SARS-CoV-2.

Viruses are made up of many proteins, called antigens, of which some are shared with other viruses – but only a few may be unique to Covid-19.

The proteins specific to the virus will trigger the production of antibodies that neutralise the virus, stopping it from replicating.

Dr Whittier said: ‘We have to figure out what part of the virus is going to be really specific for that virus.’

‘Plus some of the tests have issues with sensitivity – they may give a false negative result.’

Coronavirus ‘immunity passports’ plan is doomed to fail after only 10 per cent of Italians have developed Covid-19 antibodies, says top health official

The coronavirus ‘immunity passports’ plan is doomed to fail after only 10 per cent of Italians have developed COVID-19 antibodies, a top health official has said.

The head of the civil protection agency Silvio Brusaferro said that the ‘target is far off’ and the concept is unfeasible.

The announcement however has not stopped many regional governments – which have control over their own healthcare – from rolling out antibody blood-testing schemes.

The national government also has plans to launch a programme.

The region of Lombardy plans to start conducting immunity tests next week in the hope of issuing ‘licences’ to people found to be resistant.

Lombardy has been by far the worst-affected region in Italy, piling up more cases and deaths than many countries have done.

Health care workers will be first in line for Lombardy’s antibody tests but the regional government hopes to expand the tests to the general public.

The provinces of Bergamo, Brescia, Cremona and Lodi will have particular priority after their health systems were overwhelmed by the crisis.

Italy has registered 575 deaths over the past 24 hours, taking the total to 22,745, the second highest after America.

Dr Ryan also warned that the antibody tests raised ethical questions.

‘There are serious ethical issues around the use of such an approach and we need to address it very carefully, we also need to look at the length of protection that antibodies might give,’ he said.

‘You might have someone who believes they are seropositive (have been infected) and protected in a situation where they may be exposed and in fact they are susceptible to the disease.’

Dr Ryan said the tests had to be used as part of a coherent public health policy.

His colleague Dr Maria van Kerkhove said: ‘There are a lot of countries that are suggesting using rapid diagnostic serological tests to be able to capture what they think will be a measure of immunity.

‘Right now, we have no evidence that the use of a serological test can show that an individual has immunity or is protected from reinfection.’

She added: ‘These antibody tests will be able to measure that level of seroprevalence – that level of antibodies but that does not mean that somebody with antibodies means that they are immune.’

Dr van Kerkhove said it was ‘a good thing’ that so many tests are being developed.

But she cautioned: ‘We need to ensure that they are validated so that we know what they say they attempt to measure they are actually measuring.’

The WHO is due to issue updated guidance on the issue this weekend.

The Government has already invested in 3.5million tests, but has not yet found one reliable enough to roll out.

It was thought that the tests would allow ministers to aim for ‘herd immunity’, in which most Britons are resistant to Covid-19.

A preliminary study of Chinese coronavirus patients in Shanghai found some had ‘no detectable antibody response’ to the disease – meaning they may be vulnerable to reinfection.

Stanford University antibody testing finds California virus infections are 50 TIMES higher than reported – suggesting COVID-19 is more widespread across the US than previously thought

As much as 4 per cent of California’s population may have already been infected with coronavirus, results of antibody testing there suggest.

Scientists from Stanford University developed an antibody test for coronavirus, which detects when someone has already been infected and their body has produced immune cells that may offer protection against reinfection.

They found that between 2.5 and 5.2 percent of the people they tested were positive for antibodies.

That would mean that far more people have caught coronavirus than are accounted for in the state’s official tally which, at 28,324 cases as of Friday, comes to about 0.07 percent of the stat’s population.

However, questions remain about the accuracy of antibody tests, as well as whether the sample of people recruited to the study via online ads might draw ‘random’ test volunteers who suspect they’ve been infected.

The Stanford team has developed the equivalent of a highly ‘accurate’ test, in immunological terms.

According to their validation process, the test is between 95 and 100 per cent specific – meaning that it’s excellent at detecting antibodies developed in response to the virus that causes COVID-19, and only that virus.

The odds that it would falsely identify someone as having coronavirus when they actually have a different infection, are slim.

It’s about 80 per cent sensitive, the researching heading up the work, Dr Eran Bendavid, told DailyMail.com.

That means that 80 per cent of the time that the blood of someone confirmed to have coronavirus is run through the test, it identifies the antibodies.

Despite the 20 per cent of people that suggests it might miss, these pair of measures make it a relatively good test, compared to others and under the difficult circumstances of making a test for antibodies for a virus we know so little about.

However, the same study showed other participants had a very high antibody response.

WHO doctors say increased antibodies do not guarantee a second infection.

South Korea has identified a growing number of people who have had two separate coronavirus infections.

More than 100 tested positive for the virus having apparently already recovered from it – a shock to a country that appeared to have contained the virus through prolific testing.

The UK government pounced on an early offer of potential tests produced in China with the New York Times reporting officials agreed to pay about $20million (£16million) to secure the home testing kits.

However, when the antibody tests were put through their paces they were found not to be sufficiently accurate and as a result could not be used.

Officials are now scrambling to try to get the money back.

Downing Street did not deny the claims but the Prime Minister’s Official Spokesman said he was not aware of the specific £16million figure.

The spokesman said: ‘Where tests are shown not to have any prospect of working then we will seek to recover as much of the costs as we can.’

Officials have previously insisted that they had only purchased the minimum number of antibody test needed to conduct initial trials with full orders contingent on the kits actually working.

The coronavirus ‘immunity passports’ plan is doomed to fail after only 10 per cent of Italians have developed COVID-19 antibodies, a top health official has also said.

The head of the civil protection agency Silvio Brusaferro said that the ‘target is far off’ and the concept is unfeasible.

The announcement however has not stopped many regional governments – which have control over their own healthcare – from rolling out antibody blood-testing schemes.

The national government also has plans to launch a programme.

Mr Johnson spoke about the importance of antibody tests on March 19 as he revealed the UK was in negotiations for the kits.

He said at the time: ‘We are in negotiations today to buy a so called antibody test, as simple as a pregnancy test, that could tell whether you have had the disease.

‘And it’s early days, but if it works as its proponents claim then we will buy literally hundreds of thousands of these kits as soon as practicable because obviously it has the potential to be a total game-changer.’

Prime Minister Boris Johnson, pictured at a Downing Street press conference on March 12, said a working antibody test would be a ‘game-changer’ in the fight against coronavirus

Coronavirus testing can currently be split into two types: Antigen and antibody.

The antigen test is the one currently being carried out across the nation which shows if someone has coronavirus.

It was hoped that antibody tests would be able to show if someone has already had the disease and if they have some resistance to it which would allow that person to return to normal life.

Mass produced antibody tests had until now been seen by many as the key to restarting the UK’s creaking economy.

Health Secretary Matt Hancock announced at the start of April that he had appointed Professor John Newton as the UK’s testing tsar.

Professor John Newton told the Science and Technology Select Committee on April 8 (above) that none of the antibody tests assessed by the government so far were up to scratch

Professor Newton has been tasked with ramping up the government’s testing operation.

He told MPs on April 8 that none of the antibody tests assessed by the government so far had worked well enough to be rolled out.

He said experts had set a ‘clear target’ for the reliability of the tests but that of the devices assessed to date ‘none of them frankly were close’ to hitting it.

Despite the bleak outlook, Professor Newton insisted he and his scientists were still ‘reasonably optimistic’ of a breakthrough in the near future.