Can you have the flu without upper respiratory symptoms?

Not everybody gets every symptom every time, so it’s important to be aware of the common symptoms and know what they look like in different strains.One important strain to understand is the H3N2 strain, a strain that was highly prominent during the overwhelming 2017-2018 flu season.

Can You Have The Flu Without Upper Respiratory Symptoms?

You can, but it’s extremely rare, especially with the dominant strains (H1N1 and H3N2). H3N2 in particular causes fewer non-respiratory symptoms than other flu strains.

What Is H3N2 Flu?

H3N2 is a strain of flu that originated in pigs. This type of swine flu was one of the flu strains most responsible for the severe flu season in the winter of 2017-2018. H3N2 has risen again to prevalence, starting in India in March 2023. According to the CDC’s flu monitoring data, H3N2 is one of the dominant strains circulating in the US. Identifying H3N2 flu can be done with a diagnostic test, but in the US this test is only performed at the CDC; publicly available flu tests don’t check for specific strains.

Older individuals are more susceptible to this flu variant. Research done at the University of Pennsylvania found that people born in the late 1960s and the 1970s are more likely to get H3N2 flu because their antibodies bind to H3N2 viruses but fail to prevent infections. Dr. Scott Hensley, the study’s lead, explains that “most individuals born in the late 1960s and 1970s were immunologically imprinted with H3N2 viruses that are very different compared to contemporary H3N2 viruses. Upon infection with recent H3N2 viruses, these individuals tend to produce antibodies against regions that are conserved with older H3N2 strains and these types of antibodies typically do not prevent viral infections.” This means that an important part of managing H3N2 flu includes vaccination campaigns that target these at-risk individuals.

Differences from Other Flu Strains

Distinctions among various influenza strains, including H1N1 and influenza B, lie in their genetic makeup. H3N2 is known for its genetic variability, making it more prone to mutations that can affect its ability to evade the immune system and cause more severe illness. Compared to H1N1, H3N2 is often associated with a higher rate of hospitalization, especially among vulnerable populations such as the elderly, young children, and individuals with compromised immune systems as noted in a study done by the University of Minnesota.

Symptoms of H3N2 Strain

H3N2 is notorious for causing more severe flu seasons. The symptoms of H3N2 flu are similar to those of other flu strains but can be characterized by their intensity and rapid onset. Common symptoms include fever, chills, a non-productive cough, sore throat, body aches, fatigue, and headaches. However, individuals infected with H3N2 may experience more pronounced respiratory distress, shortness of breath, and a heightened risk of complications such as pneumonia. It’s essential to note that while these symptoms overlap with other flu types, the intensity and impact on the respiratory system often set H3N2 apart.

H3N2 flu symptoms typically manifest quickly after exposure to the virus, with an incubation period of about one to four days according to the WHO. The onset can be abrupt, and individuals may experience a sudden spike in fever, intense body aches, and respiratory symptoms. The virus primarily targets the upper respiratory tract, leading to a more severe and prolonged cough compared to other flu strains. Recognizing these specific manifestations is crucial for prompt identification and subsequent medical intervention.

Managing H3N2 Flu

If you think you have the flu, no matter what the strain is, you should talk to your doctor. Antiviral medications such as oseltamivir (Tamiflu) and zanamivir (Relenza) are most effective when administered within the first 48 hours of symptom onset. These medications can help reduce the severity and duration of illness, especially in high-risk populations. Rest, hydration, and good nutrition can help your body fight the flu– but if possible, it’s best to prevent it.

Vaccination remains a cornerstone in preventing severe outcomes associated with H3N2, and getting your shot early is crucial for building immunity before the peak of flu season. Adopting preventive measures can significantly reduce the risk of H3N2 influenza. Regular handwashing, avoiding close contact with individuals exhibiting flu-like symptoms, and practicing respiratory hygiene, including covering coughs and sneezes, are essential habits. Encouraging workplace and community hygiene practices can create a protective barrier against the spread of the virus. Strategic masking can also help protect you from the flu.

The information provided in our blog posts is for informational purposes only and is not intended as a substitute for professional medical advice, diagnosis, or treatment. Always seek the advice of your physician or other qualified health provider with any questions you may have regarding a medical condition. Never disregard professional medical advice or delay in seeking it because of something you have read on this blog.

The information provided in our blog posts is for informational purposes only and is not intended as a substitute for professional medical advice, diagnosis, or treatment. Always seek the advice of your physician or other qualified health provider with any questions you may have regarding a medical condition. Never disregard professional medical advice or delay in seeking it because of something you have read on this blog.