Three viruses that threaten the world in 2026

The world has barely recovered from the Covid-19 pandemic and three other viruses are already worrying experts. A combination of factors has favored the evolution and spread of certain pathogens.

The global scenario in 2026 presents a complex viral panorama that keeps infectious disease experts on alert.

Far from having left the pandemic era behind, a combination of factors has created increasingly favorable conditions for viruses to evolve and spread at an increasing rate.

These factors include global warming, population growth and greater human mobility.

In a published in The Conversation, Patrick Jackson, assistant professor of Infectious Diseases at the University of Virginia, in the United States, identifies three viruses that deserve special attention this year: the flu, and the little-known virus.

Although very different, all of these viruses have crossed new frontiers and expanded their reach. It is something that should not generate alarmism, but rather strategic vigilance in the face of real threats that show signs of expansion.

Oropouche

Probably the least known of the three, but increasingly cited in scientific circles, the Oropouche virus is transmitted by small mosquitoes and causes flu-like symptoms.

Identified in the 1950s in Trinidad and Tobago, for a long time it was considered restricted to the Amazon region. Since the 2000s, it has spread to other areas of South America, Central America and the Caribbean. In 2023, it resurfaced with greater intensity and the virus reached Brazil, where it killed.

They also began to emerge cases in Europe associated with infected travelers. Episodes of vertical transmission — from mother to child — and an investigation is being carried out possible relationship with diagnoses of microcephaly and fetal deaths.

The transmitting insect has already adapted to vast areas of the continent. For now, there is no vaccine or specific treatment.

Faced with this scenario, the World Health Organization (WHO) presented, on January 5, a proposal to accelerate the development of prevention and control tools against Oropouche.

H5N1 bird flu

Influenza A has always been a constant threat due to its rapid ability to mutate and the ease with which it infects different species. The last major flu pandemic, in 2009 — the so-called swine flu, caused by the strain H1N1 — caused more than 280,000 deaths in its first year.

Now, attention focuses on the H5N1known as bird flu. The virus stopped being a problem exclusive to birds in 2024, when it was first detected in dairy cows in the United States. This species jump worried experts, mainly because it was not an isolated episode: the pathogen reappeared in herds in several North American states.

Studies already suggest that several transmissions from cows to humans have occurred, many of them without apparent symptoms.

The big fear is that the virus will achieve what it has not yet achieved: adapting to transmit efficiently between people, a necessary step for the emergence of a new pandemic.

So far, the US Centers for Disease Control and Prevention (CDC) has recorded 71 human cases and two deaths since 2024, with no evidence of sustained community transmission.

Even so, specific vaccines are already being developed, as current formulations would likely not offer sufficient protection against this strain.

Mpox: two variants in global circulation

For decades, mpox was a rare disease, practically confined to specific regions of Africa. Everything changed in 2022, when access to more than a hundred countries.

Transmission through close physical contact, often during sexual intercoursetransformed this variant into a virus that now circulates recurrently in several countries.

But what is most worrying happens in parallel: since 2024, countries in Central Africa have registered an increase in infections also caused by the strain of clade Iconsidered more serious. The United States has even reported recent cases in people with no history of traveling to Africa. Although there is a vaccine, there is still no specific treatment, and experts warn that the evolution of the virus throughout 2026 could bring new health challenges.

Measles, chikungunya and other viral threats

In addition to these three protagonists, other viruses are also beginning to generate concern. , for example, caused more than 445,000 suspected and confirmed cases in 2025, with at least 155 deaths by September, according to IFL Science.

At the same time, the virus has returned to the radar following a recent outbreak in the Indian state of West Bengal, although experts emphasize that, for now, it does not demonstrate the capacity to cause a pandemic.

There are still old acquaintances, which many believed had already been controlled. , for example, has resurfaced strongly in several countries due to the drop in vaccination rateseven putting the disease’s eradication status in places like the United States at risk.

Some experts warn that viruses like HIV may increase again if cuts to international health cooperation programs continue.