H1N1 News and Research

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Novel influenza A (H1N1) is a new flu virus of swine origin that was first detected in Mexico and the United States in March and April, 2009. The first novel H1N1 patient in the United States was confirmed by laboratory testing at CDC on April 15, 2009. The second patient was confirmed on April 17, 2009. It was quickly determined that the virus was spreading from person-to-person. On April 22, CDC activated its Emergency Operations Center to better coordinate the public health response. On April 26, 2009, the United States Government declared a public health emergency.

It’s thought that novel influenza A (H1N1) flu spreads in the same way that regular seasonal influenza viruses spread; mainly through the coughs and sneezes of people who are sick with the virus.

Children remain more vulnerable to influenza despite protective antibody levels

Researchers analyzing 1,518 South African household participants found that higher pre-season antibody titers were associated with lower infection risk for three of four influenza viruses studied. Children remained more susceptible after accounting for measured exposure and antibody titers, while younger children shed viral RNA longer than older adults.

3 Aug 2026

New discovery provides insights into how seasonal influenza viruses infect people

Scientists investigating how influenza viruses replicate within cells "accidentally" discovered that different flu viruses use distinct strategies to infiltrate cells in the first place.

2 Jun 2026

Why H2N2 flu is back on the pandemic preparedness radar

A historical review in Vaccine warns that global H2N2 immunity has sharply declined since the 1957 Asian influenza pandemic, leaving most people without H2-specific protection if the virus re-emerges. The authors highlight animal reservoirs, waning birth-cohort immunity, and modern H2 vaccine platforms as key priorities for pandemic preparedness.

28 Apr 2026

Childhood flu infection leaves lasting immune imprint

A study reveals how childhood flu infections impact long-term mortality risk, highlighting implications for vaccination and future outbreak management.

17 Apr 2026

Flu vaccines protect children well across Europe, but H3N2 remains harder to stop

Influenza vaccination provided strong real-world protection for children in European primary care across two seasons, with overall vaccine effectiveness of 68% in 2022–2023 and 71% in 2023–2024. Protection was highest against influenza B and H1N1, while H3N2 showed lower and more variable effectiveness, supporting the need for higher uptake and continued monitoring.

8 Apr 2026

Targeting two influenza proteins may reduce viral transmission

A long-running debate in vaccine design revolves around whether a vaccine should be optimized to prevent the virus from replicating inside an infected host or prevent the virus from transmitting to others.

13 Mar 2026

Prior flu exposure may weaken the immune response to other strains

Prior exposure to one strain of influenza virus may weaken children's ability to mount an effective antibody response against their subsequent exposure to a different flu strain, according to a study led by Weill Cornell Medicine investigators.

11 Mar 2026

Most pandemic viruses show little adaptation before infecting humans

A new University of California San Diego study published in Cell challenges a long-standing assumption about how animal viruses become capable of sparking human epidemics and pandemics.

9 Mar 2026

Advancing influenza vaccine development: Sino Biological launches antigens for the 2026-2027 Northern Hemisphere influenza vaccine strains

The World Health Organization (WHO) has announced its recommendations for the 2026–2027 Northern Hemisphere influenza vaccine composition.

From Sino Biological Inc. 4 Mar 2026

WHO updates 2026-2027 flu vaccine composition amidst viral evolution

The World Health Organization (WHO) today announced recommendations for the viral composition of influenza (or "flu") vaccines for the 2026-2027 northern hemisphere influenza season.

27 Feb 2026

Preexisting flu immunity may offer baseline protection against avian influenza

Are seasonal flu antibodies also effective against avian flu? A team from the University of Geneva (UNIGE) has shown that a specific type of antibody associated with the former virus—already present throughout the population—may offer baseline protection against the latter.

10 Feb 2026

Overlooked animal viruses slipping past global disease surveillance

The study on Influenza D and Canine Coronavirus HuPn-2018 underscores urgent needs for targeted surveillance and diagnostics in infectious disease research.

2 Feb 2026

How pandemic viruses spread across U.S. cities before anyone notices

Researchers reconstruct the spatial spread of pandemic respiratory viruses across metropolitan areas throughout the United States

12 Jan 2026

Study compares H1N1 and COVID-19 spread across metropolitan areas in the U.S.

Public health researchers at Columbia University Mailman School of Public Health used computer modeling to reconstruct how the 2009 H1N1 flu pandemic and the 2020 COVID-19 pandemic unfolded in the U.S.

5 Jan 2026

Age and flu vaccine type influence immune activation

New research comparing four different flu vaccines found that the ability of the vaccines to activate cells of the immune system that help to protect against infection varied greatly depending on the vaccine type and age of the patient.

12 Nov 2025

New research sheds light on E. coli spread in human communities

Bacteria that often cause urinary infections can spread as rapidly as swine flu. But E. coli that are resistant to several classes of antibiotics behave differently.

4 Nov 2025

Taste-based flu test that detects infection within minutes

Researchers examine the effectiveness of a novel taste-based sensor for the early detection of influenza infection.

8 Oct 2025

New molecular sensor for taste-based detection of influenza

Flu season is fast approaching in the northern hemisphere. And a taste-based influenza test could someday have you swapping nasal swabs for chewing gum.

2 Oct 2025

Pasteurized milk contains H5N1 proteins without posing health risks

Proteins and genetic material from H5N1 influenza viruses have been found in pasteurized milk in the United States, but a study from St. Jude Children's Research Hospital shows those inactive viral pieces represent little to no health risk.

26 Sep 2025

WHO issues guidance for 2026 flu vaccine formulation in the southern hemisphere

The World Health Organization (WHO) today announced its recommendations for the viral composition of influenza vaccines for use in the 2026 influenza season in the southern hemisphere.

26 Sep 2025