H1N1

American  

Pathology.

1. a subtype of the type A influenza virus, with strains that give rise to seasonal epidemics, or sometimes pandemics, including a strain with swine, avian, and human genes responsible for swine flu.

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Etymology

Origin of H1N1

First recorded in 1970–75; abbreviation of h(aemagglutinin type)1 and n(euraminidase type) 1

Example Sentences

Public health scientists at the Columbia University Mailman School of Public Health used advanced computer simulations to trace how the 2009 H1N1 flu pandemic and the 2020 COVID-19 pandemic spread across the United States.

From Science Daily • Feb. 7, 2026

In the spring of 2009, a shift happened with an H1N1 strain, also known as swine flu.

From Salon • Jan. 8, 2026

There are also signs a different strain of flu - H1N1 - is picking up in Europe and may lead to an increase in cases here too.

From BBC • Dec. 19, 2025

Of about 3,500 influenza type A viruses genetically analyzed nationally over a recent week among public health labs, 54% were H1N1 and 46% were H3N2.

From Los Angeles Times • Feb. 11, 2025

The 1918 influenza pandemic is thought to have been caused by a reassorted combination of an H1N1 bird flu with a more common flu.

From Slate • Dec. 4, 2024