Reports of rising cases of the respiratory virus in China have dark echoes of the outbreak of the Covid-19 pandemic almost exactly five years ago.
But despite the similarities on the surface, this condition is very different and less of a concern, medical experts say.
The Chinese cases have been attributed to human metapneumovirus, known by doctors as HMPV. Here's what we know so far:
What is HMPV?
It is one of the few pathogens that circulates around the world every year and causes respiratory diseases. HMPV is very common – so common that most people will be infected as children and may have several infections during their lifetime. In countries with months of cold weather, HMPV may have an annual flu-like season, while closer to the Equator it circulates at lower levels year-round.
HMPV is similar to a better-known virus in the US – respiratory syncytial virus, or RSV, which causes flu- and Covid-related symptoms, including cough, fever, nasal congestion and wheezing.
Most HMPV infections resemble attacks of the common cold. But severe cases can result in bronchitis or pneumonia, especially among infants, the elderly, and people with weakened immune systems. Patients with preexisting lung conditions such as asthma, chronic obstructive pulmonary disease, or emphysema are at greater risk of severe outcomes.
In high-income countries, the virus is rarely fatal; Mortality is higher in low-income countries with weak health systems and poor surveillance.
How long has this virus been around?
The virus was identified in 2001, but researchers say it has spread to humans at least 60 years. Associate Professor of Pediatric Infectious Diseases at Vanderbilt University Medical Center. Leigh Howard said that although it is not new, the name influenza, Covid or even RSV is not recognized.
One reason for this is that people are rarely discussed by name unless they are hospitalized with a confirmed case.
“It's really hard to distinguish the clinical features from other viral diseases, and we don't test for HMPV as routinely as we do for Covid, influenza or RSV,” Dr. Howard said. “So most infections go unrecognized and are chalked up to anything that goes through the respiratory tract.”
How does a person become infected with HMPV?
The virus is primarily spread by droplets or aerosols from a cough or sneeze, direct contact with an infected person, or exposure to contaminated surfaces — essentially the ways people get colds, flu and Covid.
Is there a vaccine? Or treatment?
There is no vaccine against HMPV. But there is a vaccine for RSV, and because they are similar, research is underway to find a vaccine that can protect against both viruses in one shot. There is no specific antiviral treatment for HMPV; treatment focuses on symptom management.
What does China say about it?
Chinese authorities have acknowledged that HMPV cases are on the rise, but have stressed that the virus is a known entity and not a major concern. The coronavirus that causes Covid-19 was a new pathogen, so people's immune systems had not built up a defense against it.
Kan Biao, director of the Institute of Infectious Diseases of the Chinese Center for Disease Control and Prevention held a press conference on December 27. he said The incidence of HMPV among children 14 years and younger is increasing, he said. According to him, the increase was especially noticeable in the north of China. According to him, cases of influenza have also increased.
He said incidents could increase during the Lunar New Year holiday in late January, when many people travel and gather in large groups.
But overall, Mr. Kahn said, “going by the current situation, the scale and intensity of the outbreak of respiratory infectious diseases this year will be lower than last year.”
Official Chinese data shows that HMPV cases have been increasing in both outpatient and emergency settings since mid-December. According to Xinhua agencystate news agency. Some parents and social media users were unfamiliar with the virus and sought advice online, the release said; called for calm and common precautions such as washing hands frequently and avoiding crowded places.
a usual media briefing on FridayA spokesman for the Foreign Office reiterated that cases of influenza and other respiratory viruses regularly increase at this time of year, but they are “less severe and on a smaller scale than last year”.
Chinese officials said last week that it would to establish a monitoring system for pneumonia of unknown origin. This will include procedures for laboratories to report cases and for disease control and prevention agencies to investigate and manage them, state broadcaster CCTV reported.
How was the public reaction in China?
Amid online comments from people who said they had never heard of HMPV and expressed concern that it was a new pathogen, state media tried to warn people not to blindly take antiviral drugs.
Some users joked that they would finally be able to use the masks they stockpiled during the coronavirus pandemic. Many commentators have discussed the overall rise of the disease, not just HMPV: On Monday, a post on the social media platform Weibo asked, “Why does the flu hurt so much?”
What does the World Health Organization say?
WHO has not expressed concern. A spokeswoman for the organization, Dr. Margaret Harris, cited weekly reports from Chinese authorities that indicated a predictable increase in cases.
“This time of year, as expected for the Northern Hemisphere winter, there is a month-on-month increase in acute respiratory infections, including seasonal influenza, RSV and human metapneumovirus,” he said.
Should I be worried?
Reports from China are reminiscent of the early, confusing days of the Covid pandemic, and the WHO is still urging China to share more information about the origins of the outbreak five years later.
But the current situation is different in the main aspects. Covid was a previously unknown virus that passed from animals to humans. HMPV is well studied and there are ample opportunities to test it. Globally, there is widespread population-level immunity to this virus; There was none for Covid. A severe HMPV season can strain hospital capacity—especially pediatric wards—but not overwhelm medical centers.
“But it's also very important that China shares information about this outbreak in a timely manner,” said Dr. Sanjaya Senanayake, an infectious disease specialist and associate professor of medicine at the Australian National University. “This includes epidemiological data on who is infected. We will also need genomic data to confirm that HMPV is the culprit and that there are no significant mutations of concern.
Vivian Wang Prepared a report from Beijing.