More than 90% of COVID-19 patients treated with hydroxychloroquine in studies in France and Boston had longer than normal pauses in their heart beats - a sign of dangerous arrhythmias.

Evidence suggests the biggest risk factor for death by Covid-19 is age, but scores of pensioners are bucking the trend by managing to shake off the killer infection.

As a person ages, their immune system becomes suppressed and it takes longer for their body to recognise and attack the virus. Harvard scientists say this could be fixed by with NAD boosters.

DR ELLIE CANNON reveals how the oximeter, pictured, a simple tool available easily on the high street, can help catch Covid-19 before it turns deadly.

Charities in the UK have warned the killer infection can lead to acute kidney injury (AKI), a sudden serious condition that can be fatal if not treated immediately.

DR ELLIE CANNON: The Mail on Sunday's GP discusses B&Q reopening, pictured, how to obtain a free test, whether it's safe to hug grandchildren and more in this week's column.

EVE SIMMONS: Becoming infected with coronavirus undoubtedly tops the list of current health fears for most Britons. But getting fat seems to come a close second.

Dr Giorgio Gentile gave Leonard Whitehurst, being treated at Royal Cornwall Hospital, the drug tocilizumab as a last ditch attempt to save his life. He had heard promising results from early trials.

Top experts from the prestigious Royal Society concluded that masks - even home-made ones - can reduce the transmission of the deadly infection.

Gillian Assor (right), 50, who runs a nanny agency, lives in Hertfordshire, with her husband David, 51, and their children Benjamin, 23, Oliver, 21, and Isabel, 19. They came across Tommy (left).

Swiss drug maker Roche says its coronavirus antibody blood test has a specificity rate of 99.8% and a sensitivity of 100%, meaning it would show very few false positives and no false negatives

As many as 400,000 people a year in England and Wales are told they've reached the end of their treatment options, according to charity Marie Curie.

DR MARTIN SCURR: Any persistent problem can be terribly frustrating but it is not the Barrett's oesophagus (pictured) that is causing your symptoms.

New research has shown that our response to infection changes over the course of each day, and - even more importantly - that sleep disruption can leave our immune system compromised (file photo).

A new study from Rush University Medical Center looked at the protein, known as suPAR, is a marker of disease severity and aggressiveness as well as activating of the immune system.

A walk in the park could cause hayfever sufferers to sneeze, even if the pollen count is low, a US-German study has found. Research on 25 men found even a simple smell could trigger hayfever symptoms.

History shows how lethal disease pandemics have a habit of seeming to shrink away - but then returning suddenly in subsequent waves. Chillingly, these latter waves can prove far deadlier.

Leronlimab is a drug in development for treating HIV and cancer. Two of seven critically ill coronavirus patients who were given the drug were taken off ventilators in a matter of days.

One sample collected from an Arizona coronavirus patient showed a deletion of 81 genetic 'letters' that suppresses the virus's ability to fight the human immune system, also seen as SARS began to fade.

Could gadgets - such as a prong for flushing loos and covers for keyboards - help too? ADRIAN MONTI asked experts to review a selection; we then rated them.

Researchers at the London School of Economics have highlighted exactly where the UK has fallen short of protecting some 400,000 care home residents and staff.

Scientific evidence suggests that people who are overweight - which two thirds of adults in the UK are - have a 39 per cent higher risk of dying if they catch the coronavirus.

British doctors want the matchbox-sized gadgets, known as pulse oximeters, to be given to those in most urgent need for free.

An urgent review has been launched by Health Secretary Matt Hancock into whether obesity, ethnicity and gender raise the risk of death from coronavirus.

Defra confirmed it is conferring with scientists about whether wastewater can help trace the spread of the deadly infection. It could become part of the government's plan to ease Britain out of lockdown.

Sir Patrick Vallance told MPs on the Health and Social Care Select Committee that masks could have a 'marginal but positive' impact on curbing transmission of the life-threatening infection.

An interactive map using data from the Office of National Statistics (ONS) has revealed hundreds of towns and villages which have avoided a single Covid-19 fatality during the pandemic.

Leading genetic scientists analysed the genomes of the killer virus in 260 infected patients from all corners of the UK. They say they have identified 12 unique mutations (shown).

In the new survey, from PR firm Bospar, researchers found those between ages 18 and 24 were the least likely to get vaccinated against the coronavirus with only 57.8% saying they'd get the jab.

Researchers at Los Alamos National Laboratory have discovered a mutation to the coronavirus's spike protein that may make it more infectious - and it has spread around the globe.

A new study, led by Tsinghua University. found that recovered coronavirus patients had varying antibodies such as immune cells that stop the virus from attaching to our cells.

British researchers modelled how the virus would spread in three scenarios - if Italy stayed in quarantine or if movement returned to pre-lockdown levels by 20% and 40% (shown in red).

Researchers from the University of Sheffield and Los Alamos National Laboratory in New Mexico found that a newer, faster-spreading version of the virus seems to edge out the older type.

Researchers from Edinburgh and London say the approach, dubbed 'segmentation and shielding', is the only way to get the UK back to normal without overwhelming the NHS.

The UK's death toll (29,427) surpassed Italy's (29,315) today, meaning it is the worst-hit nation on the continent. But, even now, Britain's borders remain open, making it a global outlier.

The president of the Hospital Consultants and Specialists Association said Britain's testing and tracing has been 'inadequate' and questions should be asked about the timing of lockdown.

Researchers from Germany and the US explained fat cells secrete ACE-2 receptors - known as the 'gateway' into the cells of the body.

Just yesterday University of Sheffield researchers claimed that a new, more infectious type of COVID-19 had been racing through Europe. But the finding was today dismissed as 'unfounded'.

The two party leaders clashed over the pandemic as they faced each other for the first time at Prime Minister's Question in the hushed surroundings of the mostly-empty House of Commons.

Professor Lucy Yardley, from the University of Bristol, sounded the alarm today, saying evidence shows 'viral load' plays a big role in how sick someone will become.

The Scottish government has dealt a potential hammer blow to Matt Hancock's coronavirus contact tracing app as it said it will only commit to the technology if it is shown to work.

A new study from the Mount Sinai Health System found that patients on blood thinners died after about 21 days in the hospital compared to those not on the drugs who died after about 14 days.

Some institutions have said that if their coronavirus vaccine trials go well, its jab could be available as early as Fall 2020, but most people would not be able to get it until Fall 2021.

Health officials are introducing a voluntary healthy lifestyle and exercise program for the town of Huntington, Long Island, which includes free nutrition advice and fitness classes.

A new survey from The Ohio State University Wexner Medical Center found that 80% said they would be concerned to go to a scheduled prenatal appointment amid the coronavirus pandemic.

Scientists in Italy claim antibodies made against the virus in mice were able to kill the infection in human cells, but British researchers said the discovery was routine in vaccine development.

GPs and councils in England were promised the results from hundreds of thousands of swabs carried out at drive-through centres after the UK shifted to 'pillar two' of its testing scheme.

The UK drug watchdog said there'd been a surge in bogus cleansing oils and sprays appearing online. It warned these products 'pose a risk to health' and could make COVID-19 infection worse.

Scientists in Glasgow trawled over data for more than 428,000 people who were part of the UK Biobank. Some 340 of those had recently tested positive for COVID-19 in hospital.

Professor Susan Jebb, of Oxford University, urged Brits to stop buying junk food and only have healthy food in their house, and told them to exercise to avoid the temptation of the biscuit tin.