Some parents might be tempted to send their children to controversial ‘pox parties’ if a coronavirus vaccine does not come to the rescue, a top scientist has said.
Such parties were historically organised for chickenpox, but have also been used for measles, flu and other infectious diseases before vaccines were available.
At these events, parents exposed their healthy children to youngsters infected with viruses to build immunity from an early age.
Uninfected children were encouraged to play, eat, and interact with infected children to prime their immune systems so they didn’t get ill later in life.
The idea is that childhood disease is often less severe than getting infected as an adult, as is the case with many viral diseases.
But public health officials say parents are playing with fire by exposing their children to potentially life-threatening infections.
Professor Paul Lehner, a virologist at Cambridge University, said it was possible Covid-19 might one day be passed around at pox parties as a last resort option in the absence of a vaccine.
Pox parties fell out of favour in the late 1990s after the arrival of the chickenpox vaccine, but they are still sometimes used in impoverished countries which do not have easy access to jabs.
Chickenpox parties may become the norm for Covid-19 to stop children catching the disease when they are older – and suffering worse effects (stock)
Scientists speaking at a briefing said the disease spreads so well because it can make someone infectious 24 hours before they develop symptoms. This slide shows the virus progression from entry, to when the person becomes infectious, and then at seven to 11 days whether or not they need hospitalisation
The delayed body response to the virus is a ‘brilliant’ evolutionary tactic, said Professor Paul Lehner from Cambridge University, because it means people head to the races and pub while they are infectious – spreading the virus further
What is a chickenpox party?
A chickenpox party – or pox party – is where healthy children play with an infected child to ensure they also catch the virus.
This triggers an infection in their body and, hence, an immune response against the virus.
The body creates antibodies to attack the virus and T cells to remember how to fight it off, ensuring that the infection cannot occur again in later life.
Parents also deployed these events against diseases including measles and the flu because they their children would suffer much more difficult effects if they caught the disease in old age.
The parties were initially used when there were no vaccines available, but have since fallen out of favour as jabs were developed against diseases.
He told a Science Media Centre press conference today: ‘You’ll get it when you’re young, and not get sick. People will be invited to parties – like chicken pox parties – so you don’t get it when you’re older – but we’ll have to wait and see!’
Discussing an exit strategy for the pandemic, he said the virus was here to stay with the final aim being ‘herd immunity’ either through a vaccine or natural infections.
Professor Tracy Hussell, the director for inflammation research at the University of Manchester, explained at least 60 per cent of the UK population needs a level of immunity to the virus before going back to normal can be considered.
Public Health England has estimated only eight per cent of the UK has so far had the virus, and hence has a level of immunity.
Responding to MailOnline’s query whether there is a way to avoid the ‘herd immunity’ strategy, she said: ‘I think ultimately a virus works its way out of a community because most of the people become immune to it.
‘The sensitivity to herd immunity was because if we let that happen a lot of elderly people will die, and we didn’t want to go the herd immunity approach because a lot of people will die.’
She added: ‘Herd immunity is what we aim for, whether by vaccination or actual infection. Clearly vaccination is best, but herd immunity is the answer.’
Britons under 40 have just a 0.1 per cent risk of dying from an infection, modelling by the Government’s scientific advisers in SAGE spin-off SPI-M-O has revealed. But for those aged over 70 the risk may be as high as 7.2 per cent.
Office of National Statistics data shows 0.5 per cent of all fatalities (316 out of 53,030 up to October 9) have been in people aged under 40. For comparison, almost 84 per cent of all fatalities (44,384) have been in people aged over 70.
Previous studies have suggested that immunity to the virus may not persist long in people who have been struck down by the virus – and there are a handful of reported cases of re-infection.
But Professor Hussell said it was most likely that immunity would persist for longer in some populations than in others.
Professor Lehner added: ‘I agree endemic coronavirus immunity may wane, but there’s underlying background immunity which means when you get it you’re not going to get as sick.
‘We have to be optimistic and say this is the sort of thing our immune system has developed to deal with.
‘If you are born today, you’re going to be exposed to the virus at a young age.’
The scientists did not give a time for when life can return to pre-March 2020, but said a fall in hospitalisations that then stays down – in the absence of a vaccine – could be used as a bell-weather for when restrictions can start to slacken again.
‘When the hospitalisations start going down again and they stay down I think that’s the signal for going back to where we were before,’ said Professor Hussell.
Studies on patients who died from the virus in Trieste, Italy, have revealed large sections of their lungs were replaced with fibrous tissue (shown). This may cause ‘long Covid’
Infection with the virus can also cause cells to clump together. Pictured left are the cells in a healthy lung with red the cell wall and white the nucleus; and right are the cells during an infection where they have clearly clumped together
Vaccine ‘may be less effective’ for older people, scientist warns
A coronavirus vaccine may be less effective for older people, a scientist has warned.
Professor Tracy Hussell, from Manchester University, said when we age the viral alert systems in the body become ‘slower’ – a condition called immunosenescence.
When people are young the immune system is active and ready to fight off infections.
It creates T cells which remember the design of antibodies – which bind to viruses to stop them damaging cells.
These are stored in the thymus – a gland that sits above the heart.
But by the time we hit 65 this has shrunk to 40 per cent of its original size, decreasing the number of T cells in the body and reducing immunity.
‘One reason (for this) is the immune system becomes exhausted by exposure to repeated infections,’ said Hussell.
‘If you add gender into this as well, being old and male increases the risk factors even further.’
They said mass testing to pick up asymptomatic testing could also be used because it would enable people to attend venues knowing no one had Covid-19.
Professor Mauro Giacca, from King’s College London, said this tool can help people return to normality.
‘I think routine testing before some activities could help returning to a semi-normal life.
‘But it is not 100 per cent sure, but it certainly helps in addressing the problems of having a semi-normal life.’
The virus is having such a large impact because it is a type that has ‘never been seen before’, meaning it is a shock to our immune systems, they added.
It is unique from other coronaviruses, including SARS and MERS, in that someone can start spreading it without developing symptoms of the virus, and in its symptoms of loss of taste and smell and thrombosis – blocked blood vessels.
Once it infects someone the virus manages to turn someone’s nose into a ‘replication factory’ for 24 hours before they come down with an infection.
It goes undetected as it interrupts the transmission of a chemical – called interferon – which is released by cells to signal they are under attack and trigger an immune response.
‘When we look at virus infected cells we can’t even tell they are infected,’ said Professor Lehner. ‘Yet when we stain (the cells) they are screaming with virus.’
Microscopic images from infected patients have also revealed cells being broken open and coagulating together, with all their nuclei gathering in one place.
Research into patients that had died after up to 40 days in intensive care at Trieste hospital, Italy, also revealed large sections of the lung had been replaced with fibrotic tissue.
The scientists said if this persists in the lungs, it may explain why some individuals are suffering from ‘long Covid’.
A study published yesterday by King’s College London revealed as many as one in ten people under 40 could be struck by the condition.
And women were 50 per cent more likely to suffer from the condition than men.
Symptoms include chronic fatigue, chest pains and breathing difficulties.
Researchers at King’s College London made the find after using data from 4,000 contributors to the Covid Symptom Study app who had all tested positive for the coronavirus.
Studies on patients in Trieste also revealed extensive blood clotting in the lungs of patients who had succumbed to the disease
Above are cells that are abnormally fused due to infection with the virus