A vaccine against flu has been introduced in 1944 as a killed-virus vaccine, but due to high rate of mutation into the virus, new class of vaccine is launched into the market after a regular interval of research. Generally, the vaccine against the influenza virus is produced by culturing the virus in fertilized hen eggs. After isolation and purification, the viruses are carefully inactivated through different methods to destroy their infection. Before using them for vaccination, a series of tests is performed to ensure the inactivation of the viruses. Use of inactivated viruses, against a viral disease, is based on the idea to develop immunity and to improve the resistance power of body for future infection of that particular virus. After the vaccination, body prepares itself to fight against the disease within 14-17 days.
The following facts, about the flu vaccine, are essential to be aware with:
Requirement for vaccination
Regular vaccination is essential for each, as the viruses for flu are high mutable and changes its surface structure during every infection. Vaccination against the virus for a single time does not mean that the vaccine is effective forever. Intramuscular injections (flu shots) of the dose 0.5 ml of inactivated vaccine are administered.
Some flu vaccines in the form of nasal-spray (flu spray) are also available in market, which also referred as live attenuated influenza vaccine (LAIV). Attenuated vaccines contain weakened viruses instead of killed viruses (not fully inactivated but have much lowered capability for infection). People having the risk for brutal situation from flu are suggested to avoid the nasal spray for vaccination. As well as the patient suffering from severe heart and lungs problems, pregnant women, children from the age six months to two years and immuno-compromised people are advised to receive the intramuscular injection rather than nasal vaccines.
Vaccine recommendations
Vaccination can be received by anyone who is willing to minimize the risk of getting flu but there are some strict recommendations from a US agency, Centre for Disease Control and Prevention. The agency recommends vaccination for the following people:
i. Children of age between two to 19 years.
ii. Pregnant women.
iii. Patient suffering from some constant medical condition.
iv. People under strict medical supervision.
v. Health staff treating the flu patients.
The people who are not recommended for vaccination are
i. Children below six months.
ii. People having a history of vaccine hypersensitivity.
iii. People having a history of ovalbumin (egg protein) hypersensitivity.
iv. People suffering from Guillain-Barré syndrome, a rare nerve damaging disease.
Myth and veracity about the flu vaccine
Sometimes, mercury containing chemical preservative, Thimerosal, is used in flu vaccines as well as other vaccines. Mercury is regarded very harmful for mankind as it can cause serious brain injuries and sometimes triggers autoimmune diseases. Autism is another disease in children caused by mercury toxicity. But here in case, the quantity of mercury used in Thimerosal is too less to be harmful. Even Centre for Disease Control and Prevention, USA has refused to detect any symptom in vaccinated people and called it safe.
Still if, somebody is sincere to the presence of mercury preservative in flu vaccine, a Thimerosal-free vaccine can be asked for vaccination. Although, a Thimerosal-free vaccine includes certain other toxic chemicals like ethylene glycol, aluminum, formaldehyde, antibiotics like neomycin and streptomycin and sometimes phenol, these ingredients are still in too low amount to be harmful. Even a cold-drink can have comparably more chemical preservative than these classes of vaccines. So, no person going for vaccination is required to worry.
The effectiveness of the vaccine
The capability of flu vaccine to prevent a person from the attack of influenza depends upon the age and condition of the health. Humankind between the ages from six to 19 can produce antibodies against the flu virus more efficiently after the vaccination. As well as the matching quality of the killed or attenuated strain of vaccine to the encountered strain during the infection. If it matches better, vaccination will also be effective comparably better.
Side effects of vaccination
Sometimes, few common side effects are also reported like inflammation at the site of injection, fever, feeling unwell and body weakening.
