What is the Difference Between Flu A and B: Symptoms, Causes, and Treatments

Flu season can be confusing, especially when you hear about different types of influenza viruses. You may wonder what is the difference between flu A and B. In this article, you’ll learn about the distinctions between influenza A vs. B, including their influenza A vs. B symptoms, causes, and flu treatments. We’ll explore how these viruses spread and how to prevent them.

Understanding Types of Flu (Influenza Viruses)

Influenza viruses are respiratory pathogens that cause seasonal illnesses and can lead to severe complications. These viruses belong to the Orthomyxoviridae family and are classified into three main types: A, B, and C. However, types A and B are responsible for the majority of seasonal flu cases, leading to symptoms such as fever, cough, sore throat, body aches, and fatigue. Each has distinct characteristics that set them apart. 

What is Influenza A? 

Influenza A viruses are the most common and versatile of the flu viruses. They can infect humans and animals, making them particularly concerning from a public health perspective. This ability to cross species barriers allows for the emergence of new strains through a process called antigenic shift. Influenza A is further categorized into subtypes based on two surface proteins: hemagglutinin (HA) and neuraminidase (NA). There are 16 known HA subtypes and 9 NA subtypes, creating numerous possible combinations.

What is Influenza B?

Unlike Influenza A, Influenza B viruses primarily infect humans and have a more limited host range. They do not cause pandemics but can still lead to significant seasonal epidemics. Flu type A vs B is often a common question among patients. Influenza B is divided into two main lineages: Victoria and Yamagata. While generally considered less severe than Influenza A, recent studies have shown that Influenza B can be equally harmful, especially in children.

Genetic Differences: Flu A vs Flu B

The genetic makeup of Influenza A and B viruses plays a crucial role in their behavior and evolution. Influenza A viruses mutate more rapidly than Influenza B, contributing to their ability to cause pandemics. This higher mutation rate is due to a less accurate polymerase in Influenza A viruses compared to Influenza B. 

How Is the Flu Spread?

Influenza A and B viruses spread primarily through respiratory droplets when infected individuals cough, sneeze, or talk. These droplets can land in the mouths or noses of nearby people or be inhaled into the lungs. Both types of flu can also spread through indirect contact, such as touching contaminated surfaces before touching your face.

• Influenza A viruses are highly contagious and can infect both humans and animals. This ability to cross species barriers makes them particularly concerning from a public health perspective. Flu A viruses can spread rapidly, especially in crowded environments. People with flu A are most contagious during the first three days of their illness, but they can spread the virus even before symptoms appear.
• Influenza B viruses primarily infect humans and have a more limited host range than flu A. However, they can still cause significant seasonal epidemics. Like flu A, flu B spreads through respiratory droplets and contaminated surfaces. Studies have shown that approximately 37% of household influenza B virus transmission occurs via aerosols. Aerosols are smaller particles that can remain suspended in the air for long periods.

The timing and duration of flu seasons vary depending on geographic location. In the Northern Hemisphere, flu season typically runs from October to May, with peak activity between December and February. Influenza A viruses often dominate during the winter, while influenza B viruses are more prevalent in spring. 

What Are Influenza A vs B Symptoms​?

Influenza A vs B symptoms can often be very similar, making it difficult for individuals to distinguish between the two virus types. Both strains contribute to seasonal flu outbreaks and can lead to respiratory issues and discomfort. Recognizing these common signs is essential for timely diagnosis and effective treatment. Common symptoms include:

• Sudden onset of fever
• Dry cough
• Runny nose
• Sore throat
• Body aches
• Headache
• Fatigue 

However, some studies have noted subtle differences. 

• Influenza A Symptoms: Patients with influenza A tend to present with higher body temperatures (38.6°C vs. 38.3°C) and experience dyspnea more often (41.7% vs. 28%). 
• Influenza B Symptoms: Those with influenza B are more likely to experience vomiting (21.7% vs. 11.5%). 

It’s important to note that these differences are not definitive, and symptoms can overlap significantly between the two types. Flu symptoms usually last about 1 to 2 weeks, but some individuals may experience lingering fatigue or cough for several weeks after the initial infection has resolved.

What are Influenza A and B Treatment Options?

Influenza A and B treatment involves similar approaches, focusing on symptom relief and preventing complications. Flu treatment options depend on the severity of the illness and the patient’s risk factors.

For most people with mild to moderate symptoms, rest, hydration, and over-the-counter medications are sufficient to manage the flu. However, antiviral drugs can be prescribed to reduce the duration and severity of symptoms. These medications work best when started within 48 hours of symptom onset. Commonly prescribed antivirals include:

• Oseltamivir (Tamiflu): Effective in reducing the duration of flu symptoms and preventing complications. It is most effective when taken within the first 48 hours of symptom onset.
• Zanamivir (Relenza): Administered via inhalation, this medication is also effective against both types of influenza and is beneficial for patients who may not tolerate oral medications.
• Peramivir (Rapivab): An intravenous antiviral option for patients with severe illness who may have difficulty taking oral or inhaled medications.
• Baloxavir marboxil (Xofluza): A newer antiviral medication that can be taken as a single dose and is effective against influenza A and B.

Prevention Strategies: Flu Shot for Influenza A and B

Vaccination remains the most effective way to prevent influenza A and B. The CDC recommends annual flu shots for everyone six months and older. Other prevention strategies include:

1. Practicing good hand hygiene
2. Covering coughs and sneezes
3. Avoiding close contact with sick individuals
4. Staying home when ill to prevent spreading the virus to others

Flu Shot and Flu Treatment at AllCare

Proper diagnosis, treatment, and prevention strategies are key to minimizing the impact of both flu types. Annual vaccinations, good hygiene practices, and timely medical intervention can greatly reduce the spread and severity of influenza infections. If you’re experiencing flu-like symptoms, schedule an appointment with a primary care doctor at AllCare for proper diagnosis and treatment. By staying informed and taking proactive measures, we can better protect ourselves and our communities from the challenges posed by influenza A and B viruses.