Article written for DW in February 2025, edited by Fred Schwaller and Matthiew Agius.

With concerns over rising bird flu cases, experts warn of the potential for future pandemics. How prepared are we? From vaccines to surveillance, we explore how scientists are working to prevent the next global outbreak.

The rising number of human infections from bird flu in the US and other countries has health experts questioning whether these outbreaks could turn into the next pandemic.

Scientists are closely tracking the disease, particularly the highly pathogenic H5N1 strain in preparation for a potential pandemic.

But the overall risk for the global population is considered low, Matthias Tenbusch, a virologist at Universitätsklinikum Erlangen, Germany, told DW.

Scientists today have a broad toolkit to control or even prevent outbreaks, from bird flu to diseases like Marburg Virus Disease or Nipah virus infection.

Are vaccines a silver bullet?

“Vaccines are undoubtably one of the best tools scientists have to restrict future pandemics”, said Tenbusch.

Vaccines have a dual action: they protect those who receive them but also safeguard those who are not vaccinated, such as pregnant women or people with compromised immune systems. When enough people in a population have sufficient immunity — whether through prior infection or vaccination — it reduces the risks of a disease spreading to pandemic proportions. This effect is sometimes known as ’herd immunity’.

The groundbreaking scientific feat of developing a COVID-19 vaccine in under a year showcased the speed and power of modern science in tackling viral outbreaks to protect humans from diseases.

This progress was built on lessons from past outbreaks, where scientists refined vaccine technologies to respond faster and more effectively to emerging threats.

“Following the pandemic of the first SARS-CoV virus in 2002/2003, researchers figured out how a vaccine against such a virus should look like. This was extremely important knowledge when years later the SARS-CoV-2 pandemic began,” said Emanuel Wyler, a molecular biologist at the Max Delbrück Center, Germany.

New technologies like mRNA vaccines — which were awarded a Nobel prize in 2023 — scaled up during the COVID-19 pandemic. These are promising tools which experts think could improve the effectiveness of vaccines for other diseases like the flu and Zika fever.

But diseases are transmitted and behave differently so tailored vaccine strategies are needed.

In the case of H5N1 bird flu, where the virus is transmitted to humans from animals and animal products, vaccinating the animals that carry the virus and individuals who interact with infected animals is required to control the spread.

Besides the technical challenge of the vaccine development, vaccination campaign strategies are just as critical, said Wyler.

“What make vaccine campaigns really work are social, psychological and political aspects,” said Wyler.

What other tools do we have?

Pandemics occur when an infectious disease has an uncontained global spread. COVID-19 is the most recent pandemic to sweep the world. Another is the global spread of HIV, the virus that causes AIDS.

Epidemics, on the other hand, are large disease outbreaks, but often contained to specific regions.

To prevent pandemics and even epidemics occurring, scientists are identifying pathogens early on, before small-scale outbreaks grow into size.

New methods of disease surveillance have emerged as essential defense mechanisms against potential pandemics, said Wyler.

Improved genomics technologies are helping scientists analyze genetic material from environmental samples like wastewater, enabling pathogen identification, including of new diseases, before they become widespread.

These technologies are being combined with traditional surveillance like case reporting or wild bird and poultry farm testing to track H5N1 bird flu in the US. One of the key features being closely watched now is whether the H5N1 virus is mutating to favor human-to-human transmission.

Which diseases have the potential to cause new pandemics?

H5N1 is not the only virus tracked now. Mpox, Ebola, Marburg virus and human metapneumovirus  are some of the viral outbreaks being closely monitored by health agencies. But what about unknown diseases?

Javier Guzman,   director of global health policy at the US-based Center for Global Development, said around three quarters of emerging infectious diseases originate from zoonotic spillovers, where a virus jumps from animals to humans, as with bird flu, AIDS and in all likelihood COVID-19.

Scientists are using wildlife genomic surveillance and tracking to detect potential zoonotic spillovers before they spread to humans.

However, experts have warned that deforestation, wildlife trade, and rapid urbanization are increasing the likelihood of interaction with wild animals, and therefore zoonotic spillover.

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