World Health Organization (WHO) has warned that there are a total of 36 dairy cow farms in the United States infected by the outbreak of bird flu H5N1. It has been notified a related human case and 220 people are being monitored.
“The virus is adapting to mammal species, which are more similar to us than birds and, therefore, there is a higher level of alert. A higher level of alert does not mean a prediction that this will become a pandemicbut we must remain vigilant,” warned the director of the Epidemic and Pandemic Prevention and Preparedness (EPP) department of the World Health Organization (WHO), MarÃa Van Kerkhove.
Likewise, the WHO warns that “many more people” than have been reported have been exposed to infected animals. “It is important that all those exposed undergo testing or follow-upand receive care if necessary,” said the director general of the WHO, Tedros Adhanom Ghebreyesus, during a press conference that took place in Geneva (Switzerland) this Wednesday. Since the outbreak reached American cows, At least 30 people have been tested.
“Until now, the virus shows no signs of having adapted to spread among humans, but more vigilance is needed,” Tedros warned. He also recalled that the virus has been detected in raw milk in the United States, but preliminary tests show that pasteurization “kills” to the virus.
Consume pasteurized milk
The WHO’s standing advice in all countries is that people consume pasteurized milk. “Based on available information, WHO continues to assess that the public health risk posed by H5N1 avian flu is low, and low to moderate for people exposed to infected animals,” stressed the director general of the WHO.
In recent years, H5N1 has spread widely among wild birds, poultry, land and marine mammals, and now among dairy cattle. Since 2021, 28 human cases have been reported, although no human-to-human transmission has been documented in this period.
“WHO has a robust influenza surveillance system around the world, through a network of flu centers in 130 countries7 Collaborating Centers and 12 reference laboratories with the capabilities and biosafety requirements to deal with H5 viruses,” Tedros highlighted.
They also have the Influenza Pandemic Preparedness Framework, to support the rapid development and equitable vaccine distribution in case of flu pandemic. “However, there is no similar system for other pathogens, a loophole that WHO Member States are now seeking to close through the Pandemic Agreement,” she noted.
In this sense, Tedros has called for a ‘One Health’ approach that “recognize intimate ties” between the health of humans, animals and the environment.
“These two systems – one to prevent outbreaks and pandemics through a One Health approach, and another to respond to outbreaks sharing vaccines – are two vital elements of the Pandemic Agreement that WHO Member States are negotiating,” he explained.
For his part, Van Kerkhove has called for more surveillance to be carried out in animals, in poultry and wild birds, and now in dairy cattle, not only in the United States, but around the world. “Therefore, the people who are exposed to flocks infected also need to be examined,” he added.
Vaccines prepared in case of pandemic
Building on existing manufacturing technologies, WHO has worked on agreements with manufacturers to have approximately between 10 and 12% vaccines against this flu in production in real time in case it is necessary to distribute them, depending on the risk and needs.
“So there’s a lot of work going on in terms of production, in terms of increasing those capacities. But we haven’t done it yet. We haven’t started it. There are billions of vaccines that could be produced in the first year if necessary,” the United Nations health agency has indicated.
Thus, the WHO assures that, if transmission occurs between humans and if a pandemic begins, it will launch a system to “activate” a “serious” response. “There is a continuous evaluation of the risks and an update of the vaccine candidate viruses. So, for the current H5N1 in cows, we have two, but we must also take into account that there are other strains of H5 viruses circulating and we also have candidates for these other H5 virus strains All of these candidate viruses are being updated by the system and distributed to vaccine developers,” said Dr. Wenqing Zhang, director of the WHO Influenza Programme.
“If we look at the production capacity of seasonal vaccines, we will be able to have more than 8 billion doses. “That is the best estimate scenario,” he added, recalling that the seasonal flu vaccine does not protect against avian influenza.
The two vaccines against bird flu
In fact, in Europe, at the end of last February, the Committee for Medicinal Products for Human Use (CHMP) of the European Medicines Agency (EMA) adopted positive opinions for two vaccines intended for active immunization against the H5N1 subtype of the influenza A virus.
One of them, ‘Celldemic’, is intended for immunization during flu outbreaks from animals, even as public health authorities anticipate a possible pandemic. The other, Incellipan, is a pandemic preparedness vaccine intended to be used only if a pandemic has been officially declared of flu.
Thus, the director of the WHO Emergencies Program, Michael Ryan, has clarified that no vaccine has yet begun to be produced because, first of all, it is necessary to ensure that “works” against this lineage. “Our colleagues at the Centers for Disease Control and Prevention in Atlanta (United States) are testing. They are testing human sera from previously vaccinated people with H5 vaccines to look for that cross-reactivity and make sure that the vaccine candidates work,” he noted.
On the other hand, he recalled that, currently, hundreds of millions of seasonal flu vaccines are produced each year, and this new vaccine would have to change the production of the first. “So you can’t just push the button and start producing vaccines against H5. “It requires very careful consideration to decide whether or not to produce a vaccine, because you have to determine if this virus changes,” Ryan added.
However, he recalled that the virus has spread “very quickly” all over the world. “This time, not in humans, but it spread very quickly, and that’s what worries us,” she said.
