The British government has ordered tens of thousands of doses of a vaccine to protect the population in the event of a bird flu outbreak in humans. I can reveal.
A contract to supply a flu vaccine providing immunity against the deadly H5N1 virus has been launched by the UK Health Security Agency, which will be kept in stock in the event of an outbreak.
It would be ready for use from next December “in the event of zoonotic infections and for use in response to the entry of H5 influenza into the British population”, the call for tenders states.
The risk of bird flu to humans is still considered “low”, as it cannot currently be transmitted between people.
This measure, however, marks a strengthening of preparation for a possible new pandemic if the virus takes the genetic step towards human-to-human transmission.
Fears of bird flu spreading to humans have intensified following an outbreak in cattle herds in the United States.
There have been cases of bird flu in some mammals, such as sea lions and minks, but the outbreak on U.S. dairy farms is the first large-scale case where animals in regular contact with humans have contracted the virus.
It is also possible that UK poultry workers and others who work closely with birds will be routinely given the vaccine to avoid contracting the virus.
The vaccine stocks would initially be available for a period of one year, the call for tenders states.
The UK’s decision follows the European Commission signing a deal for 40 million doses of a bird flu vaccine earlier this month and was taken following public health and trade advice. to the British government. I understand.
This week, Finland announced that it would be the first country to vaccinate the population against bird flu. Farmworkers will receive two shots starting next week.
As the current strain of H5N1 has been circulating in global bird populations since late 2021, governments around the world, including the UK, have stepped up their risk assessments following the outbreak in cows in the US.
So far this year, 11 people have been infected with bird flu worldwide. In almost all cases, they were in close contact with poultry or wild birds at the time of infection. There have been two human cases of avian flu linked to the cattle outbreak in the United States.
Earlier this month, a farm worker in Mexico died of bird flu, although it was a different strain, H5N2.
He is the first human with a confirmed case of H5N2 to die, according to the World Health Organization. The 59-year-old man was hospitalized in Mexico City and died on April 24 from fever, shortness of breath, diarrhea, nausea and general discomfort, the WHO said.
The government’s latest assessment of avian influenza says the risk of avian influenza to the human population may have increased from level 3, where there is limited mammal-to-mammal transmission or transmission caused by intensive livestock farming, such as in the case of mink, to level 4, where there are “sustained and/or multispecies outbreaks in mammals; increased human zoonotic cases or limited human-to-human spread, linked to zoonotic exposures”.
How worried should we be about bird flu?
The UK’s stockpiling of bird flu vaccines – and similar measures by European Union countries – will spark fears of a new pandemic from a potentially deadly virus. So how worried should we be?
So far, there have been only a few cases in humans, with a relatively high mortality rate, but all were infected through direct contact with birds and did not transmit the virus to other people. . The overall risk to humans is considered low.
While the H5N1 strain of avian influenza has been circulating among poultry and wild birds around the world since the fall of 2021, two major developments in the past year have raised concerns among scientists that it could at some point evolve to transmit between humans.
The first of these occurred in 2023, when outbreaks began to appear among mammals, both in captivity – such as farmed mink – and in the wild, notably South American sea lions.
Even though these animals had been infected by nearby birds, there was evidence that the virus was spreading between mammals. If this so-called mammalian adaptation had been able to occur, scientists feared that further evolution, which would spread between humans, would occur.
The second development occurred earlier this year, when cows in dairy herds in the United States began developing infections. To date, the outbreak has spread to 12 US states.
Although the risk from U.S. dairy products was very low (the virus was thought to be killed by pasteurization), exposure to farmworkers and livestock producers raised fears of spread to humans, which was not a concern during the sea lion epidemic.
It was this outbreak that led the UK to raise its avian flu threat level from 3, meaning limited transmission between mammals, to a probable level 4, with more widespread transmission between mammals, although this level confidence is still low.
The UK government’s risk assessment agency still classifies a level 5 event (human outbreaks not linked to contact with infected birds or animals) as very unlikely (10-20%) or unlikely (25-35%).
And we are still a long way from Level 6, where there would be sustained human-to-human transmission and the government would have to make official public health announcements to the population.
The good news is that, unlike the outbreak of Covid, there are already vaccines in production adapted to the H5 group of influenza viruses. So if level 5 were reached in the UK, vaccines would be rolled out quickly.
This increase in risk level is, however, unreliable. Level 5 would lead to larger-scale outbreaks in humans not linked to close contact with birds or animals, while level 6 would mean sustained human-to-human transmission and trigger major announcements from government ministers and scientists on vaccine use and public health precautions.
The assessment was compiled by scientists from UKHSA, the Animal and Plant Health Agency and the Department
for Environment, Food and Rural Affairs (Defra).
Despite fears of a new pandemic, the main difference with the emergence of Covid is that H5 vaccines are already in production and could be used to target H5N1 in cases of persistent infections among humans.
The UK risk assessment indicates that there is a 10-20 per cent (very unlikely) chance that UK cattle will be infected with the same strain as the US outbreak within the next six months.
During the same period, there is a small risk – less than 5 percent – of human infection from exposure via the legal importation of unpasteurized dairy products.
In the very unlikely event that UK livestock are infected, there is a 50% chance that one or more humans will be infected, according to the risk assessment.
He adds: “The baseline risk of influenza A(H5N1) evolving to cause human transmission prior to the current outbreak in cattle was previously considered a low chance (0-5%). There is consensus that this risk has now increased.
“However, with the current limited information we cannot further assess the risk and it could be very unlikely (10-20%) or unlikely (25-35%).”
The vaccine contract announcement is expected to be made after the tender closes next month.
The Department of Health and UKHSA were unable to comment due to purdah election rules.