16 Interesting Facts about Influenza B

Influenza B is one of the four types of influenza viruses that cause seasonal flu in humans. It shares some similarities with Influenza A but also has distinct characteristics. This virus is characterized by an enveloped structure with a single-stranded RNA genome and belongs to the Orthomyxoviridae family. Influenza B further divides into two distinct lineages: B/Victoria and B/Yamagata.

Symptoms associated with Influenza B are akin to those of other influenza types. They can include fever, cough, sore throat, body aches, fatigue, and respiratory symptoms. Influenza B has the potential to cause a range of illness, from mild to severe, sometimes leading to hospitalization, and in rare instances, it can be fatal.

Influenza B typically circulates during the annual flu season, alongside Influenza A. The prevalence and the dominant lineage of Influenza B can vary from one season to the next, making it essential for healthcare authorities to monitor and adjust vaccination strategies accordingly.

Vaccination is a critical preventive measure against Influenza B. The seasonal flu vaccine is updated each year to match the prevalent strains, reducing the risk of infection and lessening the severity of the illness if infection does occur. Additionally, antiviral medications like oseltamivir (Tamiflu) can be prescribed to treat Influenza B, particularly in cases of severe illness or for individuals at high risk of complications.

Influenza B is a significant contributor to the seasonal flu burden, and its impact can vary from one season to the next. Public health efforts revolve around vaccination campaigns, surveillance, early detection, and timely treatment to minimize the impact of Influenza B and other flu strains on public health.

Influenza B Virus

Influenza B Virus (Wikimedia)

What about Influenza B interesting facts? Here are 16 interesting facts about Influenza B.

  1. Distinct Lineages: Influenza B viruses are divided into two main lineages: B/Victoria and B/Yamagata. These lineages can co-circulate during a flu season, making it challenging to predict which lineage will dominate.
  2. Humans Only: Unlike Influenza A, which can infect a variety of animal species, Influenza B primarily infects humans.
  3. Milder Symptoms: Influenza B is generally associated with milder symptoms compared to the more severe symptoms often seen in Influenza A, particularly H1N1 and H3N2 subtypes.
  4. Annual Vaccination: Influenza B is one of the strains targeted in the annual flu vaccine. The vaccine formulation is updated each year to match the specific B lineage expected to circulate.
  5. Hemagglutinin and Neuraminidase: Influenza B viruses have their own versions of hemagglutinin (H) and neuraminidase (N) proteins, which are used for classification and identification. The combinations of these proteins are designated, for example, B/Victoria/2/87.
  6. Shift and Drift: Like Influenza A, Influenza B can undergo antigenic drift (gradual changes) and antigenic shift (major changes), which can impact the effectiveness of vaccines.
  7. Symptoms in Children: Influenza B is often a significant cause of influenza-like illness in children, leading to school absences and healthcare visits.
  8. Year-Round Activity: While Influenza A tends to have a more defined seasonal peak, Influenza B can circulate throughout the year, although it’s most common during the traditional flu season.
  9. Impact on Elderly: Influenza B can have a higher impact on the elderly population, particularly those in long-term care facilities.
  10. Respiratory Infection: Influenza B primarily causes respiratory infections, affecting the upper and lower respiratory tracts.
  11. Immunity: Infection with one lineage of Influenza B does not provide significant immunity against the other lineage, contributing to the need for updated vaccines.
  12. Influenza B Viruses in Animals: While Influenza B mainly infects humans, there have been occasional reports of Influenza B infections in seals, dogs, and pigs.
  13. Viral Evolution: The ability of Influenza B to evolve and create new strains poses challenges for vaccine development and maintenance.
  14. Strain Name: The naming of Influenza B strains typically includes the virus type (B), lineage (Victoria or Yamagata), location of discovery (e.g., Brisbane), the reference strain number (e.g., 60), and the year of isolation (e.g., 2019).
  15. Cross-Protection: Prior exposure to one lineage of Influenza B may provide limited cross-protection against the other lineage, which can impact disease severity in some cases.
  16. Continual Surveillance: Ongoing surveillance and monitoring of Influenza B strains help inform vaccine composition and public health strategies to combat the virus.

Influenza B, with its unique lineages and characteristics, plays a significant role in the annual flu season. While typically associated with milder symptoms compared to Influenza A, it remains a substantial cause of respiratory infections, school absences, and healthcare visits, particularly in children. The ever-changing nature of Influenza B, its potential for antigenic drift and shift, and its ability to impact different age groups underscore the importance of ongoing surveillance and vaccination efforts. Public health organizations, researchers, and healthcare providers continue to work tirelessly to minimize the impact of Influenza B through the development of tailored vaccines and strategies to protect communities from this prevalent and evolving influenza virus.