The virus that is fueling fears of a pandemic in China has infected thousands of Americans over the past year, federal data shows.
Weekly CDC data since January 2024 shows that nearly 28,000 Americans have been infected with human metapneumovirus (HPMV), a previously little-known respiratory disease dubbed “the most important virus you’ve never heard of “.
Infections peaked in April 2024, with a peak of 1,666 positive test results in one week, or 8% 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.
On average, since Thanksgiving, 200 to 350 positive cases have been reported each week in the United States, which several health officials say is not unusual.
HMPV, which usually causes cold-like symptoms, was partly blamed on a viral outbreak in China that reportedly overwhelmed hospitals in the country’s northern provinces.
While the virus has sparked pandemic fears, rates of other winter illnesses like Covid and respiratory syncytial virus (RSV) have remained significantly higher.
For comparison, more than a million Americans have gone to emergency rooms because of RSV, and nearly 10 million have been struck down by the flu since October.
Nearly 28,000 Americans have been sick with HMPV respiratory illness since this time last year, the CDC estimates. The rise of HMPV and other respiratory illnesses has led some states to reinstate masking rules (stock image)
HMPV first appeared in 2001 and usually causes cold symptoms like cough, fever and runny nose.
But more serious symptoms such as bronchitis, bronchiolitis and pneumonia can occur, with shortness of breath, severe cough or wheezing.
Because the virus is generally mild, its exact mortality rate is unknown. But experts estimate that between 10 and 30 percent of hospitalized HMPV patients die in the United States.
In the United States, approximately 20,000 children under the age of five are hospitalized each year due to HMPV.
Similar to Covid, HMPV is spread through respiratory droplets that circulate in the air when a person coughs or sneezes.
Close personal contact, such as shaking hands or touching contaminated surfaces, can also spread the disease.
There is no vaccine or specific treatment for HMPV.
According to the latest available data from the CDC, as of the week of December 28, HMPV had a test positivity rate of 1.9 percent.
Out of about 13,800 total tests that week, that’s 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 CDC data, also from Dec. 28, the Midwestern states of Missouri, Kansas, Nebraska and Iowa had rates three times higher than the United States on average. These states constitute region 7.
MIDWEST SURGE: Region 7, which covers Missouri, Kansas, Nebraska and Iowa, is experiencing extremely high rates of HMPV compared to the rest of the country.
This map shows how the CDC breaks down different regions of the United States for its weekly distribution of respiratory infections.
Regions 1 and 2 had the lowest test positivity rates at 0.9 percent. These areas include northeastern states like Maine, New York, Massachusetts, Connecticut, and New Jersey.
Region 1 has conducted 2,270 tests while Region 2 has conducted 1,855.
While HMPV cases are increasing, other respiratory illnesses and influenza have seen larger spikes.
China is also seeing a rise in flu cases, with one in three tests coming back positive. This represents just under 7,000 new cases between December 29 and January 5.
However, China’s CDC said Thursday that the flu was showing signs of slowing while other respiratory illnesses continued to increase.
NORTHERN PROVINCES: The graph above shows the proportion of emergency visits for influenza per year in the Northern provinces
SOUTHERN PROVINCES: The graph above shows the proportion of emergency room visits for influenza per year in the Southern Provinces
In the United States, influenza and respiratory viruses are all on the rise.
According to the CDC, the level of respiratory disease activity in the United States is “high” and it is “high” or “very high” in the majority of states.
The virus with the highest level is Covid-19. Influenza and RSV are at “moderate levels.”
However, emergency room visits for influenza and RSV are “very high” and increasing, while visits are “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.
Influenza and RSV cases have reached new highs this season, with 19 percent and 13 percent of samples testing positive for these viruses, respectively, during the week ending December 28.
Around seven percent of tests were positive for Covid.
The CDC estimates that there were 1.2 million doctor visits for RSV, 60,000 hospitalizations and 3,100 deaths between October 1, 2024 and December 14.
Experts have warned that HMPV, which produces flu-like symptoms, can lurk in the body for days and can therefore be easily transmitted to others.
For Covid, the estimates are 4.9 million cases, 1.1 million visits, 130,000 hospitalizations and 15,000 deaths.
And for the flu, there are an estimated 9.3 million cases, 4.2 million visits, 140,000 hospitalizations and 13,000 deaths over the same period.
For the week ending December 28 – the latest available – 1.2 per cent of hospital visits were Covid-related, up from less than 1 per cent a month earlier.
RSV accounted for 1 percent, up from 0.6 percent a month earlier, and flu visits accounted for 5.2 percent of visits – a sharp increase from just 1 percent in the week ending on November 30.
Hospitalizations are also on the rise for all respiratory viruses and they jumped to two percent for Covid and RSV and to four percent for flu at the end of December.
Deaths increased slightly, but represented less than 1 percent of the overall death rate.
