A growing number of scientists warn that the current H5N1 avian influenza virus may be on the verge of causing a pandemic. The virus has been spreading globally since 2021, infecting birds and cattle in Texas and across the US, with dozens of human cases reported in North America.
While no clear human-to-human transmission of H5N1 has been documented yet, experts say that recent mutations in the virus make it more likely to spread among humans. Researchers have identified several key changes needed for the virus to spread widely, including mutations in its polymerase and hemagglutinin proteins.
The latest case of a severely sick teenager in Canada suggests that the virus is evolving rapidly and may be on the cusp of becoming pandemic material. The patient’s virus sequence revealed some H5N1s had changed key amino acids, which could potentially adapt it to humans.
However, researchers are still unsure if all necessary changes have been identified, and experts caution that a pandemic may occur even if one critical factor is not yet understood. Moreover, the sheer number of people needed for transmission becomes a major concern.
“The numbers game” may be at play here, says viral immunologist Scott Hensley, adding that it’s possible the virus could have had all it needed to go pandemic if only more people had been exposed to it. The global health community must remain vigilant and monitor the situation closely as experts urge governments to take proactive measures to prevent a potential outbreak.
Source: https://www.science.org/content/article/why-hasn-t-bird-flu-pandemic-started