Flu shots: how they work, why they are important, when to get them.
Flu or influenza is a disease caused by influenza virus. It is widely spread and almost everyone will get at least one infection within a few years. Every year, millions of people worldwide suffer from flu. In most cases it is harmless, but it can also be dangerous or even fatal. The most endangered are elderly, children and immune-compromised. (1)
If a lot of people get infected by a virus, we can talk about the epidemic. Influenza virus spreads among the population and causes infection. The highest incidence of flu infection is between October and May, when the most of people get infected.
How flu shots work
Under normal circumstances the human body creates antibodies for every pathogen (bacteria, virus, fungi, etc.) so that it can be prepared the next time it gets in contact with the same pathogen. Once the body gets in contact with it, antibodies will recognize it and bind to it trying to destroy it. On that way immune system prevents pathogens from multiplying and causing infection. The same applies on flu. The immune system should recognize influenza virus and destroy it before it gets out of hand. But there is only one problem. Influenza virus is prone to mutations and changes so that it hides well from the human immune system. That characteristic allows them to cause millions of infections every year.
In this case, flu shots play a significant role in disease prevention. Flu shots contain small parts of the influenza virus which causes activation of the immune system and creation of antibodies. In most cases flu shots contain influenza A virus (H1N1) and (H3N2) and influenza B virus. The next time influenza virus gets into the human body, it will be recognized and attacked and destroyed by existing antibodies so that there will be no time to develop an infection. (1)
The importance of flu shots
As we mentioned earlier, millions of people get a flu every year and thousands of them die due to flu related complications. Flu vaccines play a significant role in reducing mortality rate of flu as well as hospital stay.
Flu shots can help in prevention of cardiac complications in patients, which suffer from chronic heart diseases. They also reduce the possibility of severe diabetes complications and hospitalization.
Pregnancy can be stressful and dangerous period of life for every woman. There are major changes in the body as well as in their immune system. Some pregnant woman might be more susceptible to the flu so flu shots are important in keeping them healthy. Also, antibodies which are created in the body of a pregnant woman can be transferred to baby so it protects the baby as well during one of the most vulnerable periods.
If you have small babies or elderly near you, you should consider a flu shot for their protection too. Once you get an infection it can be easily transmitted to them. (1)
The flu vaccine does not provide 100 % safety from flu. There are cases when a person gets a flu even if he/she got a vaccine for that season.
When to get flu shots
You should get flu vaccine at least two weeks prior to start of flu season so that the immune system has enough time to prepare. It is best to schedule a vaccination at the beginning of fall. If you forgot to get a vaccine before the end of October, visit your physician and get it anyway even if it is winter now. It may be beneficial for you.
Most flu vaccines are approved for use in adults between 18 and 64 years of age. But there are some vaccine variants which are safe for older than 65 and younger than 18.
Recent recommendations are that everyone older than 6 months should get a flu shot every year to prevent flu. (1)
The most important categories for immunization are children under five years of age, elderly, pregnant woman, people which live in nursing homes, people which suffer from different chronic diseases like asthma, COPD, heart diseases, kidney diseases, liver diseases, metabolic disorders, etc. (2)
Children should get two doses of vaccine, so it is the best to start with vaccination earlier than adults.
There are no real contraindications for flu shots. If you have egg allergy, then you should get your flu shot in a hospital or other medical facility. (3)
A lot of people wonder whether flu shot can cause the flu. And the answer is, it can’t. But in some cases, flu shot, just like any other medicine or vaccine, can cause side effects. The most common are problems with injection site (redness, swelling or bump, soreness), low grade fever or aches. In case nasal spray is used as a method of vaccination, possible side effects are runny nose, headaches, vomiting, low grade fever, problems with breathing, sore throat, cough.
Sources:
1. https://www.cdc.gov/flu/protect/keyfacts.htm
2. https://www.cdc.gov/flu/about/disease/high_risk.htm
3. https://www.cdc.gov/flu/protect/whoshouldvax.htm#flu-shot
