The global surge of human metapneumovirus (HMPV) cases has ignited public concern, particularly as China grapples with increasing hospitalizations this winter. With images of crowded hospitals dominating social media, many are wondering whether this outbreak could lead to another pandemic.
Despite the alarming visuals, experts advise against panic. Dr. Carla Garcia Carreno, the Director of Infection Prevention and Control at Children's Medical Center Plano, reassured, "The concern for a pandemic can be put at rest," as the virus is not novel but rather part of the historical fabric of respiratory viruses.
HMPV, first discovered in 2001, can cause upper and lower respiratory disease. Symptoms typically include cough, fever, nasal congestion, and shortness of breath. While most cases are mild, young children, older adults, and individuals with weakened immune systems are at greater risk for severe illness. The Centers for Disease Control and Prevention (CDC) estimates HMPV accounts for approximately 10% to 12% of respiratory illnesses among children.
This virus is not unique to China; countries like India, Malaysia, and Kazakhstan have reported cases as well. Health officials worldwide, particularly from the CDC, are monitoring the situation closely. They noted, "These reports are not currently a cause for concern in the U.S.," reflecting the relatively low positivity rate for HMPV compared to flu and COVID-19.
According to the latest CDC data, HMPV infections account for less than 2% of the respiratory illnesses tested, yielding figures significantly lower than influenza, which represented almost 19%. The seasonal patterns of respiratory viruses show, as Dr. Sanjaya Senanayake from The Australian National University noted, "Respiratory infections tend to peak during the winter season." This situational backdrop likely contributes to the surge noted across northern China.
Experts attribute the current spike to several factors. China’s strict COVID-19 lockdowns allowed for limited exposure to standard respiratory illnesses, resulting in increased susceptibility as society reopened. Most respiratory viruses typically circulate during colder months, including HMPV, respiratory syncytial virus (RSV), and influenza. Dr. Andrew Catchpole, Chief Scientific Officer at hVIVO, pointed out the unlikeliness of HMPV being present at concern levels, stating, "hMPV is typically reported during the colder months; it does seem the rates of serious infection may be higher this season, but these fluctuations are fairly normal."
The discussion around HMPV reveals societal concerns of outbreaks post-COVID. With the pandemic's impact still fresh, concerns about respiratory viruses lead to heightened scrutiny of any uptick. Observing this shift, Dr. Amesh Adalja, of the Johns Hopkins Center for Health Security, remarked: "There’s just this tendency post-COVID to treat every infectious disease as an emergency when it’s not.” This perspective might help relieve some public anxiety by providing reasonable contextualization for HMPV infections relative to historical respiratory illnesses.
Alarmingly, during the last week of December 2023, the CDC reported nearly 300 confirmed HMPV cases among approximately 13,800 tests. This slight increase does not signify rampant spread compared to COVID-19 and earlier strains of influenza. With statistics demonstrating lower rates for HMPV, experts feel confident affirming, as Dr. John Tregoning declares, “This virus ... has been circulating for much longer.”
The situation deteriorated markedly last winter, as the world grappled with three significant respiratory viruses—COVID-19, HMPV, and flu, often coinciding and challenging health systems. While some feared parallels to COVID-19 characterized by rapid spread and unpredictable mutations, researchers stress: “This is very different from the Covid-19 pandemic, where no prior exposure existed.”
Transmission of HMPV occurs primarily through respiratory droplets when infected individuals cough or sneeze, as well as through surfaces. Unfortunately, unlike its contemporaries like flu and RSV, no preventive vaccine has been developed. Dr. Garcia Carreno explained, "Unfortunately, compared to flu, RSV, and COVID, we don't have a vaccine for human metapneumovirus, so we don't have the advantage of priming our immune systems to fight this virus."
Preventative measures echo the advice for other respiratory illnesses—regular hand washing, maintaining distance from infected individuals, and wearing masks when necessary. “If somebody's sick, try to avoid crowding so they don’t expose everybody, especially the vulnerable people,” Garcia Carreno added. For most, HMPV symptoms are mild and resolve within about seven days, but for high-risk individuals, discussion with healthcare providers is warranted.
Public health systems are currently putting new measures in place to monitor and report on respiratory illnesses, ensuring adequate responses for managing cases effectively. Encouragingly, as noted by the CDC, there’s no sign pointing toward a more pressing global health issue. With increased vigilance and awareness, coupled with public health guidelines, the community can stay informed without being unduly fearful of HMPV—a long-standing virus reemerging under seasonal pressures.