One of the most common diseases, Influenza is truly an epidemic of today’s age. It is a highly contagious infectious respiratory disease that manifests as a myriad of symptoms with varying degrees of severeness. It primarily affects the nose, throat and lungs. According to CDC estimates, annually, >20,000 people die from seasonal epidemics of influenza, with the majority being the very young and the very old. The best way to prevent influenza is for all patients 6 months or older to get the flu vaccine annually.
Flu viruses travel through the air in droplets, and can only travel a short distance. They are usually picked up when you come into contact with a contagious person’s sneezing or droplets from the mouth. The viruses may also be picked up by touching the same objects as an infected person, if proper hygiene is not observed.
Strains of the influenza virus change and adapt every year. Vaccine against one particular strain of virus will not protect against other, modified strains that may appear later.
- Fever (>100.4 F) +/- chills
- Sore throat
- nasal congestion
- Body aches and pains
- Fatigue and lethargy
- Red, watery eyes
- Vomiting and diarrhea are an uncommon feature of flu. They mostly occur in infants.Read more about flu in children here.
Incubation period of influenza varies from 1-4 days. A person is highly contagious during that period.
Diagnosis and Management
The gold standard for diagnosis of Influenza is by Reverse Transcriptase PCR or Viral culture of nasal secretions. Other serum markers such as full blood count, CRP etc maybe helpful in diagnosing acute infection but are not specific.
Prevention is the most effective management strategy for flu. Patients with influenza generally benefit from bed rest. Most patients with influenza recover in 3 days; however, fatigue may persist for weeks. If any underlying chronic diseases are worsened by flu (such as asthma, COPD, Diabetes), these patients may require hospital admission.
Although management of influenza is mainly supportive, with bed rest and warm fluids, there are antiviral agents available that may limit the sick period if administered early on. Oseltamivir (Tamiflu) and Zanamivir (Relenza Diskhaler) are two such agents.
Influenza vaccine provides reasonable protection against immunized strains. The vaccination becomes effective 10-14 days after administration. Specific recommendations for individuals who should be immunized can be obtained from the CDC, which publishes regular updates of this information.
All persons aged 6 months or older should receive influenza vaccine annually. Persons with a history of egg allergy who have experienced only hives after exposure to egg should receive influenza vaccine. However, a previous severe allergic reaction to influenza vaccine, regardless of the component suspected of being responsible for the reaction, is a contraindication to future receipt of the vaccine.
The CDC recommends influenza vaccine be administered during pregnancy (all trimesters); vaccination during pregnancy is shown to decrease risk of illness in the mother, as well as the risk of influenza and influenza hospitalization in their infants during the first 6 months of life.