Influenza, commonly known as Flu is a respiratory illness caused by Influenza A and B viruses. According to the World Health Organisation ( WHO), it has been listed as one of the 10 major threats to global health in 2019. It also mentions that India remains as vulnerable to Influenza as 100 years ago and recorded multiple number of cases of HINI ( Swine flu ) in 2018, causing significant morbidity and mortality. Influenza occurs in distinct outbreaks every year. It was observed that most influenza activity in Northern India was seen during the summer months while in Southern India, activity was more pronounced in winter months.
What are the signs of Flu ?:
Many people confuse Influenza with the common coldbut the two are quite distinct. In majority of cases, it is a self-limiting condition and the symptoms resolve in a few days’ time. The features are mainly of both upper and lower respiratory illness.
In adults , transmission mainly occurs from respiratory secretions when they come in contact with an infected person. This can be both from in the form of droplets or aerosols.
Once infected, the symptoms include abrupt onset of fever, headache, body ache and weakness. These can be accompanied by respiratory symptoms like dry cough, sorethroat, nasal discharge . In a small number of people, symptoms may be less dramatic with only mild cough and cold and in a few respiratory symptoms may be absent. The disease is particularly severe and complicated in high risk people for example the elderly and those with underlying heart or lung conditions.
In children, symptoms are similar to adults, mainly dominated by respiratory illness and fever. However they can also present with vomiting and diarrhoea as prominent symptoms.Small childrenparticularly the ones less than 5 years of age, more so the ones less than 6 moths are more susceptible.
Uncomplicated Flu is usually self-limiting and lasts from 3-5 days. Complicated flu can give rise to complications like severe pneumonia, superadded bacterial blood infection, heart and kidney complications leading to high morbidity and mortality. Sometimes the cough and weakness post infection can last for several weeks.
How Should Flu be managed ?:
In majority of cases of uncomplicated flu with typical signs and symptoms , particularly during seasonal outbreaks, laboratory diagnosis is not needed . However sporadic cases of flu, complicated cases with underlying medical conditions ,respiratory distress and severe disease needing hospitalisation should be tested.
Management consists of managing fever, appropriate hydration , treating superadded infections with antibiotics.
Anti-viral medications like Tamiflu ( Oseltamivir) if initiated early can reduce the duration and severity and duration of symptoms.
Can Flu be Prevented?:
Influenza is a unique virus as it changes it’s genetic composition every year , hence every single year, a new vaccine is manufactured according to the prevailing strain.
Influenza vaccine is key in protecting children and adults from flu and it’s complications.Anyone above 6 months of age can be given this vaccine annually. The protection rate of this vaccine is about 60% .
After receiving the injection, the vaccine causes antibodies to develop in the body after about two weeks, which provides protection against the virus. Traditional Flu vaccines are made to protect against three Flu viruses , an Influenza A ( H1N1-Swine Flu)) virus, an Influenza A ( H3N2) virus and an Influenza B virus . Similarly, quadrivalent vaccines are also available which protect against 4 viruses.
Flu vaccine is usually given just before the beginning of Flu season in a country. However, the vaccine can be taken throughout the flu season and still be beneficial.
The vaccine should be taken every year for two reasons. Overtime, body’s immune response reduces, hence annual vaccination is needed to rebuild the antibody levels. Also a genetic change happens in the Influenza virus strain every year , so seasonal flu vaccines are manufactured according to the prevalent strains for that year annually.
There are multiple benefits of taking Flu vaccine annually.
First and foremost is that it can keep you from getting the Flu. It prevents visit to the doctor, missing school and office, hospitalisation and becoming unwell.
In children and adults, who already have underlying medical conditions such as asthma, liver, kidney and lung diseases, it can prevent them from life threatening respiratoryillness as these groups are particularly vulnerable. It is also protects pregnant women and babies after birth. The vaccine also tends to reduce the severity and duration of respiratory illnesses. It also provides herd immunity,which means that people who are vaccinated also automatically provide protection to people who are not vaccinated.
Influenza is a potentially serious disease which can cause serious complications and the best way to protect against it is by giving annual flu vaccinations.