Why should I get vaccinated?
If you belong to the risk groups, you should in any case get vaccinated. Why run the risk of serious complications if it can be prevented? And even if you don’t belong to the risk groups, why not try to prevent a very bothersome illness that keeps you from your social life, from taking care of your children or from working? Influenza illness resolves after a limited number of days for the majority of persons, but cough and malaise can persist for more than 2 weeks. Influenza is a highly contagious acute respiratory disease and adults are infectious from the day before symptoms begin through approximately 5 days after illness onset.
Additional to your own health and income, there are other things at stake. Sickness is expensive for society. The treatment of influenza is costly, and there is a huge amount of lost working days and hence economical loss for companies and the society at large.
How long does it take after vaccination until I am protected from Influenza?
Not influenza vaccine itself is effective against the influenza virus; instead the person vaccinated develops protection in his or her body by forming substances called antibodies. Inactivated influenza vaccine is usually effective two weeks after vaccination, because then your body has made enough antibodies to protect you against the virus.
How long does the vaccination work?
Inactivated influenza vaccine works at least six months on average which is long enough to protect you for the duration of a complete influenza season. The amount of antibodies in the body is greatest 1 or 2 months after vaccination and then gradually declines.
Why do I have to get vaccinated every year?
You need to get vaccinated every year because influenza viruses change over time. Therefore the vaccine composition is adapted every year to the human influenza viruses that are circulating throughout the world that particular year.
Does Influenza vaccination give me 100% protection against catching Influenza?
Influenza vaccination can prevent symptoms of influenza by up to 90% in healthy adults and children. Among elderly the vaccine can be 50 – 60% effective in preventing hospitalization or pneumonia and 80% effective in preventing death. Vaccine efficacy against influenza respiratory illness in persons of 60 years or older is about 58%, but efficacy might be lower among those older than 70 years. Higher antibody responses can be achieved in frail elderly people by doubling the vaccine dose or a booster vaccination.
So if you are vaccinated against influenza, you have a pretty good chance of not catching it when there is an epidemic. If you do get sick, the risk of serious complications will be less than it would have been without vaccination. Influenza viruses can still change during the influenza season though, so you’re never completely without risk of catching influenza.
I am active in sports, should I be vaccinated?
Athletes who participate in team sports are more vulnerable to influenza because they are in close physical contact and share locker rooms and, often, water bottles. Overtraining can suppress your immune functions and increase your susceptibility to upper respiratory tract and other infections. Even a mild viral infection can be devastating due to loss of important training hours and/or compromise of competitive performance.
If you do not like risking an interruption in your training program or competition during the influenza season you should be vaccinated.
Can small children be vaccinated?
Children of six months or older can get vaccinated. Children should get vaccinated when they belong to any of the risk groups. Because all children aged 0 – 23 months are at substantially increased risk for influenza-related hospitalizations, vaccination of children aged 6 – 23 months and of their household contacts and out-of-home caregivers, particularly for contacts of children aged 0 – 5 months, is encouraged. Children also play a considerable role in transmitting the virus. A recent study showed that about 45% of all school-age children can catch influenza during an epidemic. Therefore it is prudent to vaccinate children who come into contact with other people belonging to high-risk groups.
Dosage recommendations for Influvac® in the European Union SPC are as follows:
| Age group |
Dose |
Number of doses |
Route |
| 6 – 35 months |
0.25 ml or
0.5 ml* |
1 or 2** |
Intramuscular or
subcutaneous |
| 36 months onward |
0.5 ml |
1 or 2** |
Intramuscular or
subcutaneous |
* There are differences in recommendation for children dosage between Member States and no sound evidence is available to justify a specific dosage.
**Not previously infected or vaccinated children should receive a second dose after at least four weeks.
Invivac® is not registered for the use in children.
Does vaccination hurt?
Many people who should get vaccinated don’t do so because they are afraid of injections. It’s good to know that injections with Influvac® are practically painless. The specially designed syringe, the DupharJect®, with which Influvac®is administered, contributes to this nearly painless application.
Does vaccination have side effects?
It is good to know that 95% of people vaccinated with Influvac® experience none or only very slight side effects. The most frequent side effect of vaccination is soreness at the vaccination site that lasts less than 2 days. These local reactions typically are mild and rarely interfere with the person's ability to conduct usual daily activities. Sometimes fever, malaise, muscle ache and other systemic symptoms can occur after vaccination and these most often affect persons who have had no prior exposure to the influenza virus antigens in the vaccine (e.g., young children). These reactions begin 6 – 12 hours after vaccination and can persist for 1 – 2 days. Allergic reactions rarely occur after influenza vaccination.
What are the side effects of influenza vaccination in children?
Less information is available for children, compared with adults. In a spontaneous reporting system the most frequently reported events among children were fever, injection-site reactions, and rash. Local pain and swelling occurs in 20 – 28% of children aged 9 months – 18 years after influenza vaccination but also after injection of a placebo. Post vaccination fever was noted among 11.5% of children aged 1 – 5 years, 4.6% among children aged 6 – 10 years, and 5.1% among children aged 11 – 15 years. Also other reactions like malaise, muscle ache can sometimes occur after vaccination and these most often affect persons who have had no prior exposure to the influenza virus antigens in the vaccine (e.g., young children). These reactions begin 6 – 12 hours after vaccination and can persist for 1 – 2 days.
Among children with high-risk medical conditions, one study of 52 children aged 6 months – 4 years reported fever among 27% and irritability and insomnia among 25%. No evidence exists of a causal relationship between influenza vaccine and neurological disorders in children.
Can vaccination cause Influenza in some cases?
No, this is a misconception. The viruses are killed first and thereafter only some particles of these killed influenza viruses are used to make the influenza vaccines. Therefore it is impossible for someone to get influenza from the vaccination, but coincidental respiratory disease unrelated to influenza can occur after vaccination. Also influenza vaccination does not offer 100% protection against influenza.
Is there a difference in side effects between vaccines?
Subunit vaccines – like Influvac® – cause the least side effects. The first available influenza vaccines contained killed whole viruses. This vaccine was effective, but caused more side effects. Over the years, companies such as Solvay Biologicals have been able to separate those parts of the virus that are not contributing to the immune response from those that are needed for a good effect. This preparation method and the advanced purification techniques rank Influvac® among the best tolerated influenza vaccines.
I’m pregnant, should I get vaccinated?
Pregnant women who have a medical condition that increases their risk for complications from influenza should be vaccinated before the influenza season, regardless of the stage of pregnancy.
If all pregnant women would be vaccinated an average of 1 – 2 hospitalizations can be prevented for every 1,000 pregnant women vaccinated. Because of the increased risk for influenza-related complications, women who will be pregnant during the influenza season should be vaccinated. Vaccination can occur in any trimester. A study of more than 2,000 pregnant women demonstrated no adverse effects on the foetus associated with influenza vaccination.
Can influenza vaccination aggravate asthmatic complaints?
The frequency of exacerbations of asthma was similar in the two weeks after the influenza vaccination and after placebo injection (29% and 28 %, respectively). The inactivated influenza vaccine is safe to administer to adults and children with asthma, including those with severe asthma. Given the morbidity of influenza, all those with asthma should receive the vaccine annually. Several studies have proved that influenza vaccination is safe among asthmatics. In a large study in adults and children with asthma, only body aches were reported somewhat more frequently after inactivated influenza vaccine (25 %) than placebo-injection (21%).
Does influenza vaccination influence recurrence of myocardial infarction or stroke?
In the elderly, vaccination against influenza is associated with a 20% reduction in the risk of hospitalization for heart disease and stroke. This reduction in hospitalization helps to explain the 50% reduction in the risk of death from all causes associated with influenza vaccination.
Why should patients with diabetes mellitus be vaccinated?
Deaths among people with diabetes increase by 5% to 15% during influenza epidemics and they are six times more likely to be hospitalized with complications from influenza than non-diabetics who have influenza. People with diabetes generally have appropriate immune responses to vaccination against influenza and this vaccination is effective in reducing hospital admissions during influenza epidemics.
I’m HIV positive; should I get an influenza vaccination?
Influenza-related death was 9.4 – 14.6/10,000 persons with acquired immunodeficiency syndrome (AIDS) compared with 0.09 – 0.10/10,000 among all persons aged 25 – 54 years. Furthermore, influenza symptoms might be prolonged and the risk for complications from influenza increased for HIV-infected persons.
Influenza vaccine was highly effective in preventing symptomatic, laboratory-confirmed influenza infection among HIV-infected persons with a mean of 400 CD4+ T-lymphocyte cells/mm3. Influenza vaccination was most effective among persons with >100 CD4+ cells and among those with <30,000 viral copies of HIV type-1/mL. Influenza vaccination has been demonstrated to produce substantial antibody titers against influenza, but among persons who have advanced HIV disease and low CD4+ T-lymphocyte cell counts, influenza vaccine might not induce protective antibody titers; a second dose of vaccine does not improve the immune response in these persons.
Because influenza can result in serious illness, and because influenza vaccination can result in the production of protective antibody titers, vaccination will benefit HIV-infected persons, including HIV-infected pregnant women.
Should I be vaccinated when I’m taking chemotherapy or immunosuppressive medication?
It is recommended you get vaccinated when you are using these medications to avoid the consequences of an influenza infection.
The highest response can be expected if chemotherapy does not precede or start immediately after the immunization and this response can be increased if a second dose is given a few weeks later. Complete protection against three influenza strains after vaccination of patients undergoing chemotherapy varied between 19% and 78%. It resulted in fewer and shorter episodes of respiratory illness and fewer out patient visits, than in those who received no vaccine.
During intensive immunosuppressive therapy, for rheumatoid arthritis, ulcerative colitis, asthma, or other diseases, the immune response after a single dose of influenza vaccine is usually lower than in healthy adults. A second dose of influenza vaccine four weeks later can improve the immune response.
I have multiple sclerosis (MS), can I get vaccinated?
Vaccination against influenza does not increase the risk of symptom exacerbation in patients with MS. In patients with relapsing multiple sclerosis (MS), an exacerbation occurred in 33% after influenza illness, whereas it occurred in only 5% of vaccinated MS patients. Because of the substantial greater risk of relapse after influenza illness, annual influenza vaccination should be offered routinely to all patients with relapsing MS.
I have allergies, can I get vaccinated?
Immediate – presumably allergic – reactions (e.g., hives, angioedema, allergic asthma, and systemic anaphylaxis) rarely occur after influenza vaccination. These reactions probably result from hypersensitivity to certain vaccine components; the majority of reactions probably are caused by residual egg protein. Information regarding vaccine components is located in package inserts from each manufacturer. Persons with allergies should first consult a physician before getting vaccinated.
I am allergic to chicken egg can I get vaccinated?
Inactivated influenza vaccine should not be administered to persons known to have anaphylactic hypersensitivity to eggs or to other components of the influenza vaccine without first consulting a physician. Persons who have had hives or swelling of the lips or tongue, or who have experienced acute respiratory distress or collapse after eating eggs should consult a physician for appropriate evaluation to help determine if vaccine should be administered. Egg protein can induce immediate hypersensitivity reactions among persons who have severe egg allergy. Also persons who have documented immunoglobulin E (IgE)-mediated hypersensitivity to eggs, including those who have had occupational asthma or other allergic responses to egg protein, might also be at increased risk for allergic reactions to influenza vaccine, and consultation with a physician should be considered. The prophylactic use of antiviral agents is an option for preventing influenza among persons hypersensitive to eggs.
Does influenza vaccination cause the Guillain-Barré Syndrome?
Patients with the Guillain-Barré Syndrome (GBS) exhibit the symptoms described by Guillain and Barré in 1916. GBS develops very quickly usually after a preceding infection. Patients with the hyper acute form of the syndrome lose the use of their legs within a day. 90% of the patients are seriously weakened during the first 3 weeks. GBS can be more serious in certain parts of the body than in others, and can even be life-threatening. The symptoms increase in intensity over a period of time, varying from a few hours in serious cases, to around 4 weeks in most patients. Patients with GBS may be almost completely paralyzed for a while. It has been shown that the symptoms might be caused by either demyelination or by a direct attack on nerve axons.
Investigations to date indicate no substantial increase in GBS associated with influenza vaccines, and that, if influenza vaccine does pose a risk, it is probably slightly more than one additional case/1 million persons vaccinated. Substantial evidence exists that multiple infectious illnesses, most notably Campylobacter jejuni, as well as upper respiratory tract infections are associated with GBS. The potential benefits of influenza vaccination in preventing serious illness, hospitalization, and death substantially outweigh the possible risks for experiencing vaccine-associated GBS. Although data are limited, for the majority of persons who have a history of GBS and who are at high risk for severe complications from influenza, the established benefits of influenza vaccination justify yearly vaccination.
Can influenza vaccine be administered safely simultaneous with other vaccines?
Inactivated subunit vaccines, like Influvac®, do not interfere with the immune response to other inactivated vaccines or to live vaccines. An inactivated vaccine can be administered either simultaneously or at any time before or after a different inactivated vaccine or live vaccine.
Who should not be vaccinated with influenza vaccine?
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Inactivated influenza vaccine should not be administered to persons known to have anaphylactic hypersensitivity to eggs or to other components of the influenza vaccine without first consulting a physician.
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Persons with acute febrile illness usually should not be vaccinated until their symptoms have abated. However, minor illnesses with or without fever do not contraindicate use of influenza vaccine, particularly among children with mild upper respiratory tract infection or allergic rhinitis.
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Whether influenza vaccination specifically might increase the risk for recurrence of Guillain-Barré Syndrome (GBS) is unknown; therefore, avoiding vaccinating persons who are not at high risk for severe influenza complications and who are known to have experienced GBS within 6 weeks after a previous influenza vaccination is prudent.
How is the composition of the vaccine determined?
Every year the World Health Organization (WHO) recommends the composition of the vaccine, based on information they get from 112 National Influenza Centers representing 83 countries all over the world. These centers inform the WHO which (new) types of influenza have been spotted in their countries. Based on the information collected through this surveillance system, the WHO recommends which strains should be included in the vaccine for the next season.
Do I still have to get vaccinated now these new influenza drugs have become available?
The new antiviral drugs are primarily used for treatment of influenza infections. Although the antiviral drugs can be used as a prophylaxis against influenza, the general consensus is that they are not a substitute for vaccination. Therefore, vaccines will remain the first line of defense in the prevention of influenza. Antivirals used as prophylaxis need to be taken during a period of 4-6 weeks (period of influenza virus circulation) and are relatively costly.
