The virus that is fueling fears of a pandemic in China has infected thousands of Americans over the past year, according to federal data.
Weekly CDC data since January 2024 shows that nearly 28,000 Americans have been sickened by human metapneumovirus (HPMV), a previously little-known respiratory disease that has been called “the most important virus you’ve never heard of.”
Infections peaked in April 2024, with 1,666 positive test results reported in one week at the peak, representing eight percent of all tests conducted that week.
The latest CDC data for the week ending December 28 shows there were 260 positive tests, a positivity rate of two percent.
Since Thanksgiving, the U.S. has averaged 200 to 350 positive cases reported each week, which some health officials say is not unusual.
HMPV, which commonly causes cold symptoms, is partly blamed for a virus outbreak in China that is reportedly overwhelming hospitals in the country’s northern provinces.
While the virus has stoked pandemic fears, rates of other winter diseases such as Covid and respiratory syncytial virus (RSV) have remained significantly higher.
By comparison, more than 1 million Americans have visited the emergency room for RSV, and nearly 10 million Americans have been struck by the flu since October.
Nearly 28,000 Americans have become ill with the respiratory disease HMPV since this time last year, the CDC estimates. The increase in HMPV and other respiratory illnesses has led some states to roll back masking rules (stock image)
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HMPV first appeared in 2001 and typically causes cold symptoms such as coughing, fever and runny nose.
But more serious symptoms can occur, such as bronchitis, bronchiolitis and pneumonia, with patients experiencing shortness of breath, severe coughing or wheezing.
Because the virus is usually mild, the exact fatality rate is unknown. But experts estimate that in the US, between 10 and 30 percent of patients hospitalized with HMPV die.
Approximately 20,000 American children under the age of five are hospitalized with HMPV each year.
Similar to Covid, HMPV spreads through respiratory droplets that circulate in the air when someone coughs or sneezes.
Close personal contact, such as shaking hands and touching contaminated surfaces, can also spread the disease.
There are no vaccines or specific treatments for HMPV.
According to the latest available CDC data, HMPV had a test positivity rate of 1.9 percent as of the week of December 28.
Of the approximately 13,800 total tests for the week, that amounts to just under 300 confirmed cases.
The test positivity rate for the week of November 30 was 0.9, half that of the following month.
And this time last year, the CDC recorded a test positivity rate of 1.2 percent.
According to regional data from the CDC, also as of Dec. 28, the Midwestern states of Missouri, Kansas, Nebraska and Iowa had an average of three times the U.S. These states form Region 7.
MIDWEST SURGE: Region 7, which includes Missouri, Kansas, Nebraska and Iowa, has sky-high HMPV rates compared to the rest of the country
This map shows how the CDC breaks down different regions of the US for the weekly breakdown of respiratory infections
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Regions 1 and 2 had the lowest test positivity rates at 0.9 percent. These areas include northeastern states such as Maine, New York, Massachusetts, Connecticut and New Jersey.
Region 1 conducted 2,270 tests, while Region 2 conducted 1,855 tests.
While HMPV cases are increasing, other respiratory illnesses and influenza have seen larger spikes.
China is also seeing spikes in flu cases, with one in three tests coming back positive. This amounts to just under 7,000 new cases from December 29 to January 5.
However, China’s CDC said Thursday that the flu is showing signs of slowing down, while other respiratory illnesses continue to rise.
NORTHERN PROVINCES: The graph above shows the percentage of emergency department visits due to influenza per year in the northern provinces
SOUTHERN PROVINCES: The graph above shows the percentage of emergency room visits due to influenza per year in the southern provinces
Flu and respiratory viruses are all on the rise in the US.
According to the CDC, the level of respiratory disease activity in the US is “high” and in most states it is “high” or “very high.”
The virus with the highest level is Covid-19. Flu and RSV are at ‘moderate levels’.
However, the number of emergency room visits for flu and RSV is ‘very high’ and increasing, while the number of visits is ‘low’ but increasing for Covid-19.
The states with the highest levels of respiratory activity were Kansas, Oklahoma, Texas, Arizona, Utah, Louisiana, Tennessee, Kentucky, Georgia and Florida.
Cases of influenza and RSV reached new highs this season, with 19 percent and 13 percent of samples, respectively, testing positive for those viruses in the week ending December 28.
About seven percent of tests were positive for Covid.
The CDC estimates that between October 1, 2024 and December 14, there have been 1.2 million doctor visits due to RSV, 60,000 hospitalizations and 3,100 deaths.
Experts have warned that HMPV, which causes flu-like symptoms, can linger in the body for days and can easily be passed on to others.
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For Covid, estimates are 4.9 million cases, 1.1 million visits, 130,000 hospitalizations and 15,000 deaths.
And for the flu, estimates are 9.3 million cases, 4.2 million visits, 140,000 hospitalizations and 13,000 deaths in the same period.
For the week ending December 28 – the latest available – 1.2 percent of hospital visits were for Covid-19, up from less than one percent a month earlier.
RSV accounted for one percent, up from 0.6 percent a month earlier, and flu visits accounted for 5.2 percent of visits – a sharp increase from just one percent in the week ending November 30.
Hospital admissions have also risen for all respiratory viruses, rising to two per cent for Covid and RSV and four per cent for flu at the end of December.
The number of deaths has increased slightly, but is less than one percent of the total mortality rate.