In 2021, New HMPV Variants Emerged in Spain Drove Disease Severity Yet No Genomic Surveillance of What is Happening Today

Medical News: The Rising Threat of Human Metapneumovirus
In 2021, Spain witnessed a dramatic resurgence of human metapneumovirus (HMPV) infections. New variants of this respiratory virus emerged, triggering an alarming increase in disease severity. While scientists in Barcelona meticulously analyzed these variants then, the lack of sustained genomic surveillance today leaves the global community vulnerable to new outbreaks, such as the ongoing HMPV surge in China.
https://www.journalofinfection.com/article/S0163-4453(23)00262-1/fulltext
 
Doctors and Health officials should refrain from making public claims that HMPV infections are mild till genomic data is available to clearly show that no new strains, subtypes or lineages spotting new mutations are at play or that past more worrisome strains that had been identified are behind the new surges.
 
Yes, HMPV is not a new virus and has been in circulation since it was first discovered in 2001 and even then, it had been found to cause worrying outcomes in those in the vulnerable groups such as infants, the elderly and those that are immunocompromised. Further besides the fact that here are no known antivirals or vaccines for HMPV so far, we have very research on HMPV, its pathogenesis and its effects on long term health. We however have published proof that the HMPV is constantly evolving and mutating. A key question that the general public should pose to many of these garbage doctors and health officials is that if HMPV is mild ..why are many that are infected often needing to be hospitalized?
 
Also note that typical ordinary strains of HMPV have a mortality rate of about 10 percent, higher that flu that is 9 percent and higher than RSV and many other respiratory pathogens except SARS-CoV-2.
https://annalsofintensivecare.springeropen.com/articles/10.1186/s13613-023-01117-w
 
HMPV, a member of the Pneumoviridae family, causes respiratory infections that range from mild cold-like symptoms to severe lower respiratory tract infections. Vulnerable groups, including young children, older adults, and immunocompromised individuals, are particularly at risk. This Medical News report sheds light on how the emergence of these new variants escalated health crises and explores the pressing need for genomic monitoring.
 
An Overview of HMPV and Its Variants
HMPV is an enveloped, single-stranded RNA virus, closely related to the human respiratory syncytial virus (HRSV). Its genome encodes nine proteins that are integral to its replication and virulence. Two major genotypes, HMPV-A and HMPV-B, are further divided into subgenotypes A1, A2 (A2a, A2b, A2c), B1, and B2 (B2a, B2b).
 
Studies in 2021, led by researchers at a university hospital in Barcelona, highlighted the significant role of the G protein in HMPV evolution. This protein’s attachment ectodomain has undergone duplications that enhance the virus's ability to evade immune responses. Specifically, duplications of 180 and 111 nucleotides have been linked to severe infections in adults, particularly lower respiratory tract infections (LRTIs).
 
Key Findings From the 2021 Outbreak in Spain
During the 2021 outbreak, HMPV’s circulation in Spain exhibited distinct patterns. The researchers observed an unprecedented rise in cases following a disruption in viral activity during the COVID-19 pandemic. These findings, supported by whole-genome sequencing (WGS) and phylogenetic analyses, shed light on how pandemic-related measures influenced viral dynamics.
 
Seasonal Disruptions and Epidemic Peaks
Traditionally, HMPV infections follow a seasonal pattern with clear annual peaks. However, the pandemic halted HMPV’s circulation in 2020. By the summer of 2021, HMPV re-emerged alongside HRSV, resulting in two epidemic peaks. The second peak in autumn recorded a higher prevalence, likely driven by two generations lacking prior exposure to HMPV due to pandemic-related precautions.
 
The Role of Co-Infections
The study reported an increase in co-detections with adenovirus, rhinovirus, bocavirus, and enterovirus during this period. Interestingly, the prevalence of co-infections surged post-pandemic, indicating a shift in viral interactions.
 
Demographics and Risk Factors
Before the pandemic, HMPV predominantly affected children under two years old, with a higher tendency in male infants. However, in 2021, females and adults over 50 years were disproportionately affected, highlighting an unexpected shift in demographic susceptibility.
 
Genetic Evolution and Enhanced Virulence
A significant finding from the Spanish study was the dominance of the A2c subgenotype, particularly variants carrying 111-nucleotide duplications. These duplications were associated with increased fusogenicity, allowing the virus to invade host cells more efficiently. Enhanced membrane fusion and immune evasion capabilities of these variants correlated with severe disease outcomes.

Similar patterns were observed following the 2009 influenza A(H1N1)pdm09 pandemic, where HMPV A2c variants also exhibited high genetic distances and increased morbidity. The 2021 variants’ aggressive dominance further underscores their potential for public health crises.
 
Current Concerns: The Chinese Outbreak
While Spain’s 2021 outbreak was a wake-up call, the global response has been insufficient. At present, China faces a major HMPV outbreak, with speculation about a newly emerged neurotropic lineage.
https://www.thailandmedical.news/news/human-metapneumovirus-infections-on-the-rise-in-china
 
https://www.thailandmedical.news/news/emerging-novel-lineages-of-human-metapneumovirus-in-china-mark-the-start-of-2025
 
https://www.thailandmedical.news/news/hmpv-infections-and-hospitalizations-continue-to-rise-in-china-while-researchers-are-focusing-on-the-new-lineages-from-subtype-a2
 
Reports indicate an overwhelming demand for ICU care due to encephalitis and cognitive impairments in infected individuals, alongside respiratory symptoms.
 
Cases are rapidly spreading to neighboring countries like India and Indonesia.
https://www.thailandmedical.news/news/breaking-several-cases-of-human-metapneumovirus-hmpv-found-in-indonesia
 
https://www.thailandmedical.news/news/three-month-old-female-infant-becomes-second-hmpv-case-in-bengaluru-india
 
Latest data also shows that HMPV infections are rising in the United Kingdom.
https://www.thailandmedical.news/news/influenza-positivity-rate-in-united-kingdom-rises-to-29-5-percent-hmpv-infections-also-rising
 
The Urgent Need for Genomic Surveillance
The resurgence of HMPV highlights the importance of sustained genomic surveillance. Regular monitoring of viral evolution is crucial to identify new variants, assess their impact on public health, and develop targeted interventions. The lack of ongoing surveillance leaves the world unprepared for potential pandemics, as seen with the Chinese outbreak.
 
Conclusions
The study from Barcelona emphasized the importance of virological surveillance and genomic analysis in understanding HMPV dynamics. By documenting the evolutionary trajectory of HMPV, researchers provided critical insights into its potential to disrupt public health systems. However, the absence of continuous genomic surveillance is a glaring gap that needs immediate attention.
 
HMPV remains a significant cause of morbidity across all age groups, with its genetic diversity presenting ongoing challenges. Countries worldwide must establish robust surveillance systems to monitor and contain the virus. Without such measures, future outbreaks could pose even greater threats to global health.
 
For the latest HMPV News, keep on logging to Thailand Medical News.
 
Read Also:
https://www.thailandmedical.news/news/californian-study-confirms-hpmv-is-neurotropic-and-causes-cns-issues-like-febrile-seizures-and-fatal-encephalitis-in-children
 
https://www.thailandmedical.news/news/doctors-warn-that-hmpv-can-trigger-deaths-in-children-with-covid-19
 
https://www.thailandmedical.news/articles/hmpv-human-metapneumovirus