Understanding Influenza B: The Lesser Known Virus
, by AussiePharmaDirect, 9 min reading time
, by AussiePharmaDirect, 9 min reading time
Influenza, or simply “the flu”, is a common respiratory illness that can be found worldwide. There are four types of influenza viruses: Influenza A, Influenza B, Influenza C, and Influenza D. Among these types, Influenza A and Influenza B are the most common and frequently encountered. You can't escape it; chances are, you've had a not-so-pleasant encounter with it at some point in your life. While it may not generate the same level of global impact as Influenza A, it remains an important player in seasonal flu activity.
In this blog, we will delve deeper into what influenza B is, exploring its characteristics, transmission patterns, impact on public health and some tips on prevention and improving our resilience against the flu.
Unlike Influenza A, Influenza B does not have subtypes but is classified into distinct lineages, such as Yamagata and Victoria. It is known to cause localised outbreaks and can lead to a significant number of flu cases, albeit on a smaller scale compared to Influenza A.
Regarding the ecology of the virus, Influenza B has a complex interaction with its natural hosts. Influenza B is primarily associated with human-to-human transmission and exhibits seasonal patterns of activity. In addition to humans, some evidence suggests that Influenza B viruses can infect seals and ferrets, although their significance in the overall ecology of the virus remains relatively limited compared to the human population. Certain subtypes of Influenza A viruses, on the other hand, have occasionally been transmitted from animals to humans. This is known as zoonotic transmission and has occurred in cases such as avian influenza (H5N1) or the swine flu (H1N1).
In temperate regions, Influenza B typically causes outbreaks during the winter months, similar to other respiratory viruses. The virus can persist and spread more easily in colder and drier conditions, allowing it to thrive during the winter season.
Just like its other influenza siblings, it is a highly contagious respiratory virus that can spread easily from person to person. When an individual infected with influenza B coughs, sneezes, or talks, they release respiratory droplets containing the virus into the air. These droplets can be inhaled by nearby individuals, leading to the transmission of the virus.
In addition to inhalation, influenza B can also spread through direct contact. If an infected person has the virus on their hands and touches surfaces or objects, they can contaminate those surfaces. When another person touches the contaminated surface and then touches their mouth, nose, or eyes, they can introduce the virus into their own body, potentially causing an infection.
So, how long are you contagious with the flu? Influenza B is most contagious during the first few days of illness when symptoms are most severe. However, infected individuals can still spread the virus before symptoms appear or even if they have mild symptoms.
Common symptoms of influenza B include:
These symptoms can vary in intensity and may overlap with other respiratory illnesses. Influenza B symptoms can resemble those of the common cold, but the flu tends to cause more severe symptoms and rapid onset of illness.
Influenza B can lead to various health complications, especially in individuals who are more vulnerable or have weakened immune systems. Some common complications associated with influenza B include:
Exacerbation of underlying conditions: Influenza B infection can worsen chronic conditions, such as diabetes, respiratory diseases, or immune disorders.
Experiencing flu-like symptoms for an extended duration, such as 3 weeks, may raise concerns and indicate the possibility of complications or an underlying condition. While the typical duration of uncomplicated influenza is usually around one to two weeks, the severity and duration of symptoms can vary among individuals.
It's important to monitor your symptoms closely and seek medical advice if:
It is possible to have both influenza A and influenza B at the same time. During flu season, multiple strains of influenza viruses can circulate in the community. It is not uncommon for individuals to be infected with more than one strain or type of influenza virus simultaneously. This co-infection can occur if a person is exposed to multiple strains of influenza viruses at the same time or during separate instances of exposure.
There are antigen test kits available that you can use as a preliminary measure to get an indication of whether you may have the virus. These test kits are designed for home use and can detect the presence of flu antigens in respiratory samples such as nasal swabs
Once diagnosed with influenza B, treatment options are available to help manage the illness. Antiviral medications, such as oseltamivir (Tamiflu), zanamivir (Relenza), and peramivir (Rapivab), can be prescribed by healthcare professionals. These medications work by inhibiting the replication of the influenza virus, thereby reducing the duration and severity of symptoms.
These antiviral medications are most effective when initiated early in the course of the illness, ideally within the first 48 hours of symptom onset. They can help shorten the duration of symptoms by a day or two and potentially reduce the risk of complications.
In addition to antiviral treatment, supportive care is crucial in managing influenza B symptoms. This includes getting plenty of rest, staying hydrated, using over-the-counter pain relievers (under medical guidance), and implementing measures to alleviate symptoms such as fever, cough, and congestion.
Prevention through vaccination is the most effective strategy to reduce the risk of influenza B infection. Annual flu vaccines are designed to provide protection against the most prevalent strains of influenza viruses expected to circulate in a given flu season. You can schedule a flu vaccination for yourself by contacting your healthcare provider, local clinic, or pharmacy to inquire about availability and appointment options. It is recommended to get vaccinated before the flu season starts, as it takes about two weeks for the vaccine to provide optimal protection.