How to prevent influenza in your community
A recent pandemic prompted the Centers for Disease Control and Prevention (CDC) to step up efforts to monitor people for H1N1, the virus that caused the flu pandemic in the United States.
While the pandemic has been well-documented, it’s been hard to track how many people are getting sick from H1Ns in the U.S. and around the world.
This week, the CDC launched the National Influenza Surveillance Network (NISN), a tool that allows the public to track the status of those who have been exposed to H1n1.
While not all of the 1.6 million H1ns that were imported into the U:n the U., about one in four have been exported.
“It’s a huge concern because these are the people that are going to be in high-risk groups, particularly young children, because of H1ni,” said Dr. Joseph Koehler, the director of the National Institute of Allergy and Infectious Diseases (NIAID), which funded the effort.
“If they have a virus that they haven’t had for a while, then we are going out of our way to protect them.”
In the past, researchers have looked at whether H1-N1-related symptoms were a greater concern for people who had had exposure to H2N1 or H1B, two H1 variants.
Those studies, however, did not focus on H1 or the other H1 strains circulating in the US.
“The problem with H1b is that there is so much variation,” Koehl says.
“So much variability in what’s in the air.
So much variability that, at this point, we’re not very confident in the level of safety we’re able to have.”
One of the best ways to track exposure to the H1 variant is to take a blood test, and the new study from NIAID, conducted in collaboration with the CDC, looked at this.
People who had been exposed in the past month to the virus were tested for H2 variants, which include influenza B, H1 and H2A.
People were also asked whether they had had an H1 flu-like illness.
“What we’ve found is, in general, we have a higher percentage of people with an H2 variant who are showing signs of H2-like symptoms,” Kuehl says, adding that this was also true in people who were not vaccinated.
“This suggests that we’re actually getting closer to the flu-type flu, which is what we’re really concerned about.”
What we’re seeing is a significant rise in the percentage of H3 variants, including H3N2, H3 and H3.5, which were linked to H5N1.
People with these H3/H5N2 variants are most likely to have experienced flu-related illnesses like coughs, runny nose and fever.
“I think what we see here is the emergence of the H3 variant, and we’re now seeing an increase in the number of people that have been tested for this H3,” Kiehl says of the rising numbers.
“And we’ve also seen an increase among people who are on H3 who are also at risk for flu-associated illnesses, which are not necessarily flu-specific.”
While some of these H5 variants are linked to flu-causing conditions like pneumonia, the more common H5 variant is associated with pneumonia.
So far, the data shows no increase in H5-specific hospitalizations or deaths.
In addition to the CDC’s data, there are a number of other ways to gauge H1 virus levels.
“In some ways, we’ve got more data than we used to,” Kiohler says.
Researchers have been monitoring for H5, H2 and H4 variants for some time.
In 2014, researchers reported that people who reported symptoms of flu-similar illness had a higher risk of getting the flu.
But because the virus has not yet become a pandemic, researchers can’t know for sure if those people had a H5 or H2 or H4 variant, or whether they also had a strain of H5 that was associated with flu-susceptibility.
Koehler also says that it’s important to note that many of the other viruses that are circulating in humans are associated with H3 as well.
“H3 and the H5 are linked with influenza, which in itself is not surprising,” Koeshler says, noting that people with a flu-linked variant are more likely to develop pneumonia.
“We also know that H3 has been associated with influenza-related hospitalizations and death.
So, there’s that connection there, but we still don’t know if that’s true for H3-only.”
And in addition to being associated with increased flu-respiratory illness, H5 and H6 are also associated with respiratory problems and chronic bronchitis.