The number of pathogens that could cause the next pandemic has risen to more than 30 and now includes influenza A virus, dengue virus and monkeypox virus, according to one updated list this week from the World Health Organization (WHO) was published. Researchers say the list of “priority pathogens” will help organizations decide where to focus their efforts in developing treatments, vaccines and diagnostics.

“It's very comprehensive,” says Neelika Malavige, an immunologist at the University of Sri Jayewardenepura in Colombo, Sri Lanka, who was involved in the effort. She studies the family of Flaviviridae viruses, which includes the virus that Dengue fever caused.

The priority pathogens, published in a July 30 report, were chosen for their potential to cause a global human public health emergency such as a pandemic. This was based on evidence showing that the pathogens were highly transmissible and virulent and that access to vaccines and treatments was limited. The WHO's two previous efforts in 2017 and 2018 identified about a dozen prioritized pathogens.

“The prioritization process helps identify critical knowledge gaps that need to be urgently addressed” and ensures the efficient use of resources, says Ana Maria Henao Restrepo, who leads the WHO Epidemics R&D Blueprint team that produced the report.

It's important to check these lists regularly for relevant ones global changes in Climate change, deforestation, urbanization, international travel and more, says Malavige.

The latest effort identified risky pathogens across entire families of viruses and bacteria, broadening their scope.

Mpox and smallpox

More than 200 scientists spent about two years evaluating evidence on 1,652 species of pathogens - mostly viruses and some bacteria - to decide which should be added to the list.

The group of coronaviruses known as coronaviruses is one of the more than 30 priority pathogensSarbecovirusare known, which include SARS-CoV-2 – the virus that causes the global COVID-19 pandemic – andMerbecovirus, which include the virus that causes Middle East Respiratory Syndrome ( MERS ). Previous lists included the specific viruses that cause severe acute respiratory syndrome (SARS) and MERS, but not the entire subgenus to which they belong.

The new additions to the list also include the Monkeypox virus, which will be released in 2022 global Mpox outbreak caused and continues in Bags in Central Africa is widespread. The virus is considered a priority, as is its relative, the variola virus, which causes smallpox, although they were eradicated in 1980. This is because due to the fact that people are no longer routinely vaccinated against the virus and therefore do not gain immunity to it, a unwanted release which could trigger a pandemic. The virus could potentially be used “by terrorists as a biological weapon,” says Malavige.

Six influenza A viruses are now on the list, including subtype H5, which is one Outbreak in cattle in the United States. Among the five bacteria - all newly added - are strains that cause cholera, plague, dysentery, diarrhea and pneumonia.

Two rodent viruses were also added because they have spread to humans and there is sporadic human-to-human transmission. The report said climate change and increased urbanization could increase the risk of these viruses being transmitted to people. The bat-borne one Nipah virus remains on the list because it is fatal to animals and highly transmissible, and there are currently no treatments that protect against it.

Many of the priority pathogens are currently limited to certain regions but have the potential to spread globally, says Naomi Forrester-Soto, a virologist at the Pirbright Institute near Woking, Britain, who was also involved in the analysis. She studies the family Togaviridae, which includes the virus that causes chikungunya. “There is no specific place that is most at risk,” she says.

‘Prototype’ pathogens

In addition to the list of priority pathogens, researchers have also created a separate list of 'prototype' pathogens that could serve as model species for basic research and the development of therapies and vaccines. “This could help encourage more research into less studied viruses and bacteria,” says Forrester-Soto.

For example, before the COVID-19 pandemic, there were no available human vaccines for any of the coronaviruses, says Malik Peiris, a virologist at the University of Hong Kong who was part of the Coronaviridae research group. Developing vaccines for a member of the family will give the scientific community confidence that it is better equipped to address a significant public health emergency for these viruses, he says. This also applies to treatments, he says, because “many antiviral agents work against a whole group of viruses.”

Forrester-Soto says the list of pathogens is reasonable based on what researchers know about the viruses. But "some pathogens on the list may never cause an epidemic, and one we haven't thought about may be important in the future," she says. “We almost never predicted the next emerging pathogen.”