Reports of a sharp rise in respiratory virus cases in China have evoked dark echoes of the beginning of the coronavirus pandemic almost exactly five years ago.
But despite the superficial similarities, medical experts say the situation is very different and nothing to worry about.
The cases in China are reported to be caused by human metapneumovirus, known to doctors as HMPV. Here's what we know so far:
What is HMPV?
It is one of several pathogens that cause respiratory illnesses in epidemics around the world each year. HMPV is common. It is so common that most people are infected when they are still children and may experience several infections during their lifetime. In countries with cold weather for several months, HMPV can circulate annually, similar to influenza, but in areas close to the equator it circulates at low levels year-round.
HMPV is similar to respiratory syncytial virus (RSV), a virus well known in the United States. HMPV causes symptoms that are very similar to those associated with influenza and the new coronavirus, including cough, fever, stuffy nose, and wheezing.
Most HMPV infections are mild and resemble a cold attack. However, in severe cases, it can cause bronchitis and pneumonia, especially in young children, the elderly, and people with weakened immune systems. Patients with pre-existing lung conditions such as asthma, chronic obstructive pulmonary disease, and emphysema are at increased risk for severe outcomes.
In high-income countries, the virus is rarely fatal. Deaths are more common in low-income countries due to weak health systems and inadequate monitoring.
How long has this virus been around?
The virus was identified in 2001, but researchers say it has been circulating in humans for at least 60 years. Dr. Lee Howard, associate professor of pediatric infectious diseases at Vanderbilt University Medical Center, said the disease is not new, but it's not as well-known as the flu, coronavirus or even respiratory syncytial virus.
One reason for this is that the name of the disease is rarely talked about, except when people are hospitalized with confirmed infection.
“The clinical features are very difficult to distinguish from other viral diseases, and we do not routinely test for HMPV as we do for COVID-19, influenza, and RSV,” Howard said. said the doctor. “As a result, most infections go unrecognized and are thought to be caused by respiratory infections.”
How do people become infected with HMPV?
The virus is primarily spread through droplets or aerosols from coughing or sneezing, direct contact with an infected person, or exposure to contaminated surfaces. This is basically the same way people get colds, the flu, and the coronavirus.
Is there a vaccine? Or a cure?
There is no vaccine against HMPV. However, there is a vaccine for RSV, and because both viruses are similar, research is underway to find a vaccine that can protect against both viruses with a single dose. There are no specific antiviral treatments 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 stress that the virus is known and is not a major concern. The coronavirus that causes Covid-19 was a new pathogen, so people's immune systems had not built up defenses against it.
At a press conference held by the Chinese Center for Disease Control and Prevention on December 27, Kang Pyou, director of the Center's Institute of Infectious Diseases, said that the number of HMPV infections among children under 14 years of age is increasing. . He said the increase was particularly pronounced in northern China. Influenza cases are also on the rise.
He said cases could spike during the Lunar New Year holiday at the end of January, when many people travel and gather in large groups.
But overall, Prime Minister Suga said, “Judging by the current situation, the scale and intensity of the spread of respiratory infections this year will be lower than last year.”
According to the state-run Xinhua News Agency, official Chinese data shows that HMPV cases have been increasing in both outpatient and emergency patients since mid-December. The report said some parents and social media users were unfamiliar with the virus and sought advice online. He urged people to remain calm and take normal precautions, such as washing their hands frequently and avoiding crowded places.
At a regular press conference on Friday, a Ministry of Foreign Affairs spokesperson said that although cases of influenza and other respiratory viruses typically increase at this time of year, “the severity is lower than in previous years, and the scale of the spread has also increased.” It seems small,” he repeated. ”
Chinese authorities announced last week that they would set up a surveillance system for pneumonia of unknown origin. This includes procedures for laboratories to report cases and for disease control and prevention agencies to confirm and deal with cases, state broadcaster CCTV reported.
What was the public reaction in China?
Amid comments online from people saying they had never heard of HMPV or expressing concern that it was a new pathogen, state media warned people not to take antiviral drugs blindly and warned people not to take antiviral drugs blindly. I am trying to reassure you.
Some users joked that they were finally able to use up all the masks they had hoarded during the coronavirus pandemic. “Why does the flu hurt so much” trended on social media platform Weibo on Monday, with many commenters discussing the rise in not just HMPV but the disease overall.
What does the World Health Organization say?
WHO has not expressed concern. Dr. Margaret Harris, a spokeswoman for the group, cited weekly reports from Chinese authorities showing a predictable rise in cases.
“At this time of year, as expected in the Northern Hemisphere winter, acute respiratory infections such as seasonal influenza, respiratory syncytial virus, and human metapneumovirus are increasing month-on-month,” she said in an email.
Should I be worried?
Reports from China are reminiscent of those from the chaotic first days of the coronavirus pandemic, with WHO still urging China to share more information about its origins five years later. There is.
However, the current situation is different in important ways. The new coronavirus is a previously unknown virus that was transmitted from animals to humans. HMPV is well studied and there is widespread ability to test for HMPV. There is widespread population-level immunity to this virus around the world. There was nothing for Covid. A severe HMPV season can strain the capacity of hospitals, especially pediatric wards, but does not overload medical centers.
“But it is also important for China to share data on this outbreak in a timely manner,” said Dr. Sanjaya Senanayake, an infectious disease expert and associate professor of medicine at the Australian National University. “This will include epidemiological data on who is infected. We will also need genomic data to confirm that HMPV is the cause and that there are no significant mutations of concern.”
Vivian Wang contributed reporting from Beijing.
