INFLUENZA VACCINES: How well does it work

What is Influenza or flu?
Influenza (flu), caused by influenza virus, is a contagious respiratory illness that affects the nasal passage, throat and sometimes lungs causing mild to severe illness. This virus is easily transmitted from person-to-person via droplets. This infection is usually characterized by sudden onset of high fever , headache, aching muscles, nonproductive cough and sore throat. Serious outcomes of this infection

Why is it important to get vaccinated for the influenza?
In 1918-1919, a global pandemic of influenza killed about 5 crore people. Since then, we have encountered many pandemics (1957, 1968, 2009-2010) of Influenza , affecting and killing crores of people. This virus has the ability to mutate and replicate rapidly, and hence, it becomes difficult to model a vaccine which would provide a lifelong Immunity .

Antigenic "drift" and "shift" (random genetic mutations of infectious agent) is the main reason why people get flu even after the vaccine is received, and also the sole reason why the vaccine composition must be assessed, and updated every year. If the vaccine is updated and provided to individuals every year, then the chance of pandemic virus to re- emerge appears to be faraway.

How effective is the influenza vaccines?
In general, there are 2 types of flu vaccines, injections (killed virus) and nasal spray vaccines (attenuated virus). The vaccine becomes effective against the flu virus within two weeks of administration. Each year, influenza virus changes slightly, making the seasonal vaccine used in previous years less effective. The effectiveness of the seasonal flu vaccine is dependent upon the extent of the match between the virus strains used to prepare the vaccine and those viruses in actual circulation in the community. The age and Health status of the individual also play a vital role in determining the vaccine effectiveness.

Microorganisms adapt and evolve. Due to this nature, it is necessary to prepare new vaccines every year, because previous year's vaccine may or may not protect you the next year. New flu vaccines are released every year to keep up with rapidly adapting flu viruses.

Flu Shot: Your Best Bet for Avoiding Flu! Flu is a serious infection, which is caused by the influenza viruses. Not only those individuals who have weak immune system are affected, but the individuals with strong immunity are also affected. These infectious viruses can spread through infected droplets that enter another person's body. From there, the viruses takes hold and begin to develop. Hence, its essential to get a shot for prevention. Flu shots are not taken only when an individual catches a flu, but can also be taken to prevent them.

What are the benefits of flu shots?

Flu vaccination can keep the infections at bay: Flu vaccine has shown to reduce the risk of having to go to the doctor with flu by 40 to 60%. It prevented over 53 lakh flu illnesses and 85,000 influenzaassociated hospitalizations. Hence, its safe to say, "A shot per year keeps the doctor away!"

Flu vaccination reduces the risk of flu associated hospitalization: Pediatric deaths from flu were reduced to half for children with high-risk medical conditions and by two-thirds for healthy children. As mentioned in the above point, Influenza hospitalizations were reduced to half for all adults including >60 years of age.?

Vaccination gives protection to women during and after pregnancy: During pregnancy, there can be changes in the immune system which increases the risk of severe illness and hospitalization. Hence, it is recommended to get a shot as the infection can pass on to the baby. If flu shot is taken during pregnancy, it not only protects the mother but also the baby as the anti-flu antibodies produced can be passed on through breast milk. The flu shot can be received during any trimester of pregnancy

Flu vaccine can lifeguard children: Influenza vaccine can save a child from the risk of dying from influenza. Hence, it is important to get a flu shot every year.

Flu vaccination reduces the severity of illness in people who get vaccinated but still fall sick. Flu vaccination reduced deaths, ICU admissions and length of stay, and overall duration of hospitalization among flu patients.

What are the types of Flu Vaccines?
Majorly there are two types of vaccines available, they are: Inactivated Influenza Vaccine (Trivalent or Quadravalent): It is given to the individuals aged 6 months and above, including pregnant women and patients with underlying medical conditions. The dose is injected into the deltoid muscle. As the vaccine name suggests, the viruses included in the vaccines are inactivated so that they do not cause flu. But sometimes, minor side effects like fever , muscle pain, etc, can be noticed.

Live Attenuated Influenza Vaccines (LAIV): This vaccine is approved only for the individuals aged 2-49 years. This vaccine is contraindicated in pregnancy. It is basically sprayed into the nose. This vaccine is made from attenuated viruses and does not cause influenza. Mild symptoms like fever, sore throat, nasal congestion can be seen.

Influenza Vaccine for Flu as well as Cold Cold and flu both have same symptoms, people usually mistake flu for cold. It should be always kept in mind that flu is caused by influenza virus and cold can be caused by various types of viruses. Also, cold is common and can be cured easily without any vaccines, whereas flu requires a vaccine. Hence, flu vaccines does not prevent common cold.

Effects of Vaccine on Children and Elderly: Children and elderly are more prone to the influenza virus, as a child's body is in the stage of developing immune system, whereas in elderly, the immune system weakens. Hence, it is important to vaccinate these age groups for preventing the risk of deaths. But the type of vaccines for an age group of 65 years is different. First is High Dose Flu Vaccine, which contains 4 times the amount of antigens as compared to the regular flu shots. The second one, Adjuvant Flu Vaccine, which is made with MF59 adjuvant, an addictive that creates a stronger immune response ir the body.

What are the Side effects of Flu Vaccines?
A. Mild side effects can be noticed like:
- Fever
- Sore throat
- Swelling at injection site

B. Rare and serious side effects like:
Allergic reactions
Difficulty in breathing
Swelling around eyes or lips
High fever
Dizziness
Racing heart

Besides Vaccine, is Flu Avoidable?
The answer is YES! Here is what can be done

- Avoid crowd: It can be difficult to avoid crowd, but if a limited contact is persisted, then the risk of getting flu can be reduced.

- Wash hands regularly: It is necessary to wash hands, especially before eating and preparing food , as the flu virus can stay live on hard surfaces for 24 hours.

- Sleep, stress, diet: These three things should be maintained in order to build up the immune system.

- Cover mouth and nose: These simple habits can make you avoid the flu.