Although the search for protection against the coronavirus disease COVID-19 temporarily blocked information about vaccinations against other diseases in the Internet space, they should not be forgotten. In particular, about a billion people in the world can get sick with the flu every year. Of these, approximately 3-5 million have severe illness. And hundreds of thousands of cases (approximately 250-650 thousand) are fatal. Such an important vaccination against influenza can prevent them. 

The mortality caused by this virus depends, among other things, on the specific strains of the pathogen, which can change every season.

For example, in Ukraine in the cold season of 2018-2019, about 5.4 million people fell ill, and 65 cases were fatal. Whereas in 2009 more than a thousand people died from influenza in the country.

Vaccination is one of the best ways to protect yourself from the flu and its possible complications: vaccination reduces the risk of contracting the flu by 60% or more.

True, in rare cases, the introduction of a vaccine can cause certain complications. But experts say: severe reactions in the form of anaphylaxis are rare and amount to about 1.35 cases per million injections of the drug. And mild and moderate reactions, of which the majority, can hardly be called significant compared to the complications that the flu itself can lead to.

REASONS OF HYPERSENSITIVITY TO THE INFLUENZA VACCINE

Most flu vaccines today are grown from egg embryos and therefore contain small amounts of an egg white called ovalbumin.

While not all manufacturers specify the amount of ovalbumin in their vaccines, those who did it from 2011-12 to 2014-15 reported a maximum amount of ≤1 mcg / 0.5 ml per injection dose for influenza and 0. 24 μg / 0.2 ml for nasal vaccine.

Until recently, the presence of egg white was considered one of the main contraindications for vaccination, because about 1.3% of children and 0.2% of adults suffer from allergies to the proteins of bird eggs in the world.

However, during the Vataline Safety Datalink experiment, in which more than 7.4 million doses of inactivated trivalent influenza vaccine (IIV3) were administered to people, scientists recorded 10 cases of anaphylaxis. But in doing so, the researchers found that most of these reactions were not associated with the egg white in the vaccine.

Thus, the study did not rule out the likelihood of severe hypersensitivity to influenza vaccine due to chicken egg protein, but states that such a chance is very small and does not exceed the likelihood of reactions to other components.

Other causes of a hypersensitivity reaction to a flu shot can be preservatives, stabilizers, latex (as a rule, contact with it occurs with the direct administration of the vaccine).

For example, a mercury-based preservative called thimerosal is used in some multi-dose vials of influenza vaccines. It is used to prevent the growth of bacteria and other microbes.  

On the one hand, the presence of this component in vaccines is considered safe, on the other hand, the American specialized medical departments (the American Academy of Pediatrics and the US Health Service) have called for the removal of thimerosal from vaccinations for newborns. However, there are already influenza vaccines that do not contain it.

FLU VACCINATION ALLERGY SYMPTOMS

But we must remember that the body’s response to a flu shot is not always an allergy. Quite often, other symptoms develop that are attributed to non-allergic side effects of immunization.

Common adverse reactions to the flu shot include: 

· Pain, swelling or redness at the injection site;      

· Slight fever;      

· Slight body aches;      

· Headache;      

· Nausea;      

Runny nose,      

· Cough – in the case of vaccination in the form of drops.      

Most of these side effects usually go away on their own after one to two days.

One of the rare side effects of influenza vaccination is Guillain-Barré Syndrome (GBS) . This autoimmune disorder causes damage to the nervous system and is more common after getting the flu than after getting vaccinated against it. Also GBS is not associated with a nasal spray vaccine. 

Some studies have estimated the risk of HBS after vaccination as less than 1 or 2 cases per million people vaccinated.

GBS usually begins with weakness, pain, or tingling in the feet or legs (especially in children).

Also, with GBS, you can observe:

• loss of coordination;      

· Problems with speech, swallowing or chewing;      

· The severity of control of the eye muscles;      

• vision problems;      

· Shortness of breath;      

· Violation of the heart rhythm;      

• digestive problems;      

· Inability to control urination.      

Most people with GBS recover completely. However, this process can take quite a long time. And in some cases, GBS can cause permanent muscle weakness or paralysis.

IMPORTANT POINTS FOR VACCINATION

Points to be aware of if you are allergic to the flu vaccine:

Perhaps most importantly, most severe allergic reactions, the same anaphylaxis, usually develop immediately (in the first 30 minutes) or within 2 hours after the injection. That is why, if there is a risk of its occurrence, it is important not to leave the medical facility under medical supervision for at least 30 minutes after vaccination.

The main signs of anaphylaxis:

· Swelling of the lips, face, tongue or throat;      

· Rash or hives;      

· Shortness of breath;      

· Wheezing;      

· Rapid heartbeat;      

· Nausea and vomiting;      

· Dizziness, fainting;      

· Lethargy;      

· A sense of doom.      

If anaphylaxis is not treated immediately, shock, coma, suffocation, heart or respiratory failure, and death can develop.

As noted, vaccine-induced anaphylaxis is rare.

If a severe reaction does occur, it must be borne in mind that it can recur within 12 hours. This is the so-called biphasic anaphylaxis.

And much more frequent are relatively mild reactions that do not pose a threat to life.

These reactions are often delayed. That is, it may well appear the next day after vaccination.

A small rash at the injection site is not considered a serious allergic reaction. And the soreness at the injection site should go away on its own within one to two days.

WHO CAN GET THE INFLUENZA VACCINATION?

Today, there are such recommendations for immunization against influenza:

· Vaccination is allowed for pregnant women, but not for children under 6 months of age.       

· People diagnosed with egg protein allergy can get the flu vaccine with medical supervision for 30 minutes after the injection.       

· A patient with a previous history of severe allergic reaction to influenza vaccine, regardless of which component may have provoked such a response, should not be re-vaccinated against influenza.       

· If a patient develops Guillain-Barré Syndrome after the vaccine has been administered, a doctor should be consulted before the next vaccination.       

· There are already flu vaccines on the world market that are completely devoid of egg components.