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

The 2009 H1N1 flu pandemic led to 274,304 hospitalizations and 12,469 deaths.

From Science Daily • Feb. 7, 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

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

He put a human flu virus — H3N2 — into one pig, and a swine flu virus — H1N1 — into another.

From Los Angeles Times • Nov. 26, 2024

For example, when H1N1, also known as swine flu, emerged in Mexico in the spring of 2009, tens of thousands of mild cases went undetected, causing health authorities to overestimate the severity of the disease.

From Salon • Jul. 23, 2024