Should we get vaccinate against Influenza and which vaccine to use? Winter 2022-2023 edition
(And also, what is swine flu, and can the vaccine cause disease? And how does it relate to Covid-19? And why did my grandma’s neighbor told her that he didn’t get the vaccine last year because the year before he had the flu? And many other questions)
The upcoming winter is getting closer again and with it, mainly the talk about the flu.
It seems that until the Corona era, no vaccine was as controversial as the flu vaccine. In this case too, people all over the world were divide into two – those who get vaccinated faithfully every year and those who never get vaccinated.
So, a little bit about the flu, the connection between the flu and Corona, the flu vaccine and my recommendation to you and your family at the end.
Covid-19 and the flu
There’s an elephant in the room and we have to talk about it.
Does COVID-19 waive the need for a flu vaccine or vice-versa? In my opinion, these things are unrelated.
No-one expected that there will not be a single flu case in many countries two seasons ago and no-one knows what will the flu activity be in the upcoming season.
Either way, the things are unrelated and I recommend everyone, see the end of this article, to get the flu vaccine without apprehension regardless of Covid-19.
What is the flu virus actually, and what are the different types of the flu virus?
Flu is a disease cause by a regular virus called Influenza that divides into three groups called A/B/C. Viruses of the first two groups (A and B) are the most common disease-causing pathogens and cause epidemics (local plague).
The viruses of the different groups are further divided into subtypes according to two glycosylated proteins on the viral envelope that determine its specific serotype and responsible for its virulence.
The proteins are called Hemagglutinin (marked as H and there are 15 types) and Neuraminidase (marked N and there are 9 types).
There’s even another division to sub-sub types of species, within the same type of virus. I don’t think it’s necessary to go into such detail, although they possibly have clinical significance.
But why am I rambling about these flu subtypes?
Given that type A has a complicated epidemiology that involves many birds and mammals that serve as reservoirs for subtypes with potential to infect humans, and given that the influenza virus tends to go through many mutations and genetic switches between the human and animal virus, potentially, each one of the antigen groups of H and N that exist in animals are of pathogenic potential in humans.
Small changes in the virus are called tiny antigenic changes (antigenic drift) and large changes are called significant antigenic changes (antigenic shift).
This is the reason why the flu virus is of global interest, because beyond local endemics, it has the potential to cause pandemics (world plague).
This will happen if after a significant antigenic change, a new virus unknown to humans will enter circulation.
Indeed, many past plagues have taught us of this deadly potential.
An example of a past Influenza plague that took place in the world
The deadliest plague of all influenza plagues occurred between the years 1918-1920 and is called ‘the Spanish plague’.
It is estimated that this plague hit between 20-40% of world’s population and killed more than 20 Million people.
Surely, the poor hygienic conditions and lack of supportive care for the patients contributed to the high mortality rates back then, but this is a classic example of a new strain of influenza virus that hit the entire globe with great intensity.
What is the swine Flu?
When you understand the issue of the different types of influenza viruses, then you can understand that once every few years a new species of influenza virus appears. This species is named after its origin, usually animals.
For example, influenza type A/H1N1 that origins in a genetic switch of a human, swine and bird influenza virus, entered circulation in the year 2009 and got the name ‘The swine flu’.
Is it really important what’s the name of a specific influenza virus that arrives?
The name is of-course not important and it’s now clear that the virus that causes swine flu does not necessarily cause a more severe disease than a virus that didn’t get such a name.
The fear was (and still is) of a new strain of virus against which the population is not properly immunized and may therefore cause more significant morbidity.
How can you predict what types of influenza viruses are expected to arrive this upcoming winter (2022-2023) to any country?
The World Health Organization (WHO) monitors morbidity and types of influenza species that hit the Southern hemisphere where it precedes the Northern hemisphere.
How does one catch influenza?
Transmission of influenza is by droplets. This means, droplets from the ill person’s respiratory system pass on to the mucus membrane (mouth, nose, eyes) of another person. Contact with surfaces or hands that have saliva on them for example, is very contagious. Practically I can say from experience that in most homes that I diagnosed the flu (I perform a quick flu test to suitable cases in winter), there was more than one patient in the household. That’s shows the high transmission rates of this virus.
What disease does the Influenza virus cause?
A true infection with the influenza virus causes significant and unpleasant disease.
I am repeating this sentence because it’s important: A true infection with the influenza virus causes significant and unpleasant disease.
Why did I emphasize the word ‘true’? Because everyone thinks they know whether they had or hadn’t gotten sick with the flu when in fact, this is usually not the case.
Many of the people who have a cold with or without fever during winter are sure they have the flu.
But usually when the illness is this mild, it isn’t the flu but another respiratory virus (you can call it flu like).
On the other hand, many people with high fever and cough that are diagnosed as bacterial pneumonia after five days, are certain they had bacterial pneumonia but in fact the whole illness was influenza without any bacterial complication.
Only by a certified lab test (usually in the set-up of the emergency room or inpatients) or quick antigen test (performed by few clinics) one can really diagnose influenza.
But influenza is a difficult disease and usually includes fever higher than 38 degrees, sometimes chills and muscle ache, runny nose, throat aches, nagging cough, head ache and shortness of breath. The disease duration is between 3-7 days. I define influenza as a disease that ‘destroys’ you.
The illness is more severe in patients that are weaker, including babies and small children, elderly and people who suffer significant background illnesses.
Also pregnant women and morbidly obese individuals are at higher risk for severe disease.
Among the common complications of influenza, it’s possible to find secondary bacterial infections such as pneumonia, sinusitis or ear infections. There are other complications, including neurologic and cardiac complications, but they are not common.
Add Covid-19 to the equation this year, mainly the fact that it will be difficult to distinguish these two infections and we will reach an unequivocal conclusion – if it’s possible to prevent the flu, we must do so.
Is there treatment for the flu?
Practically, there are very few medications against the influenza virus but the most common is Oseltamivir (Tamiflu). Its mechanism of action includes inhibition of neuraminidase and is effective against viruses of the A and B groups.
Infectious diseases experts are in disagreement about the actual efficacy of this medication and what’s clear is, that in order for it to do something and shorten the disease it should be started at an early stage of the disease.
According to some health authorities, treatment should be initiated in one of two cases: the first – a patient is part of a group of high risk for severe disease and the second – a patient suffering from severe disease symptoms.
Personally, I would not count on any of the medications to make a significant difference. As stated, one must remember that not only is the flu a severe disease, due to body weakness and involvement of the respiratory system, bacterial complications can be found after an infection with influenza.
Complications may be severe such as bacterial pneumonia, bacteremia (bacteria in the bloodstream) and more.
In small children, bacterial ear infections (otitis media) can be seen secondary to influenza.
Antibiotic treatment doesn’t change the disease course of influenza and should be reserved for those cases with an actual suspicion or diagnosis of a secondary bacterial infection.
Because it’s very difficult to distinguish between the symptoms of influenza and those of sinusitis or bacterial pneumonia for example, many of the people who actually only have influenza receive unnecessary antibiotic treatment.
Is there prevention of the flu?
Seasonal flu vaccines are given at the start of every winter season. The composition of species changes every year according to the WHO recommendations and based on data from the Southern hemisphere.
In the 2022-2023 season several different vaccines will be available, most of them are against 4 species (as opposed to previous years). Inactivated vaccines against 4 species (names for example – Influvac-Tetra, Vaxifrip-Tetra, Fluarix-Tetra and more).
A live-attenuated vaccine that is given as a nasal spray (Flumist).
What species of Influenza will the vaccine include this year?
Last winter, according to the WHO decision the four species included in the different vaccines were:
B species Austria
B species Phuket
Why should you vaccinate against the flu every year?
Because a universal vaccine that suits all the species comprehensively and causes long term immune memory has not been invented yet.
Who can and should receive the flu vaccine?
Inactivated vaccine – theoretically any person over the age of 6 months.
Live-attenuated vaccine (Flumist) – registered only for ages 2 to 50 years, note below, that there are other populations who should not receive the live-attenuated vaccine.
Who cannot receive the inactivated influenza vaccines?
People with a severe allergic reaction to egg protein in the past should only be vaccinated in a healthcare establishment where they can be treated in case of a severe reaction.
People who experienced a severe allergic reaction to a previous influenza vaccine in the past cannot be vaccinated.
People (children or adults) who are suffering from a current acute moderate to severe disease accompanied by fever, better wait until after recovery for the vaccine. At this point I’d like to expand a little because I hear many parents that wanted to vaccinate the child but in practice didn’t because of a cold and a cough without fever. Whoever postpones the vaccine because of a cold can miss the flu season. May I remind you, during winter many kids have the common cold and cough for the entire season. That’s why I only recommend to postpone the vaccine if there’s a disease with fever.
Warning only – people who had Guillain-Barre syndrome within 6 weeks of a previous influenza vaccine.
All other people above the age of 6 months may be vaccinated. Also, immune compromised persons may receive a vaccine. It’s possible for people who are immune compromised to have a weaker immune reaction, but there’s no actual way to quantify this and there’s no reason to avoid the vaccine.
Who cannot receive the live-attenuated influenza vaccines (Flumist)?
Children under two years of age or older than 50 years.
People who experienced a severe allergic reaction after any previous influenza vaccine.
People with an impairment or suspected of impairment of their immune system, congenital or acquired.
Wheezing in the preceding three days, or oral steroid treatment, or people who required hospitalization in the intensive care unit due to an asthmatic exacerbation. People who receive treatment with a steroid inhaler of any dose may get vaccinated.
People ages 2-17 years who take long term treatment with medicines of the salicylate group (such as aspirin).
People of any health condition that may cause aspiration or impair the ability of the respiratory system to deal with excretions such as spinal injuries etc.
People with cerebrospinal fluid leak or cochlear implants.
People (children or adults) who are suffering from a current acute moderate to severe disease with or without fever, including people with severe nasal discharge – better wait until after recovery for the vaccine.
People who received antiviral medication for influenza in the preceding two days before the vaccine. Administration of this medication to those receiving the live attenuated vaccine also during the two weeks after the vaccine is not recommended because it may impair the efficacy of the vaccine.
Warning only – people who had Guillain-Barre syndrome within 6 weeks of a previous influenza vaccine.
Warning only – people who are at high risk of developing complications as a result of an infection with influenza including chronic lung disease (not asthma), heart and vascular diseases, liver/kidney disease, neurologic, hematologic or metabolic diseases including diabetes.
In short, one may say that the live-attenutated vaccine is suitable only for individuals between the ages 2-50 years who are generally healthy.
Important important important – some health authorities recommend that a person who received a live-attenuated vaccine should not be in contact with people with severe immune compromise that require an environment protected from pathogens within a week of the vaccine.
Is there any connection between the corona and flu vaccines?
No, the recommendation this year too will be to get vaccinated against both diseases.
What are the side-effects of the inactivated influenza vaccines?
The most common side-effect is a local reaction at the vaccine site, that is, sensitivity at the injection site the continues for 24/48 hours after the vaccine.
More mild systemic effects such as a mild fever, a little muscle ache, cough etc. – may occur at 24/48 hours after the vaccine.
Many times, I’ve heard of people who swore to have been sick with the flu following the vaccine. It’s possible that the virus was incubating in their bodies as they were getting the vaccine, but usually this shows a misunderstanding of what real influenza is.
The inactivated vaccine cannot cause disease or the flu. Point blank.
What are the side-effects of the live-attenuated influenza vaccine?
The most common side effects include runny nose, congestion, nose bleed and throat ache. Goes on for 1-3 days after the vaccine. Systemic side effects such as fever, head ache, muscle and tummy ache and more – are less common but may also continue for 1-3 days after the vaccine.
How can babies under the age of 6 months be vaccinated against the flu?
Babies under the age of 6 months cannot be vaccinated, but they may be protected by:
Breastfeeding – partial or full breastfeeding by a vaccinated mother transfers the antibodies to the baby passively. A lactating mother may be vaccinated with any influenza vaccine including the live-attenuated vaccine.
Immunization of all other family members – this to prevent the virus from “entering the house”.
Who has to (in my opinion) get the flu vaccine?
In my humble opinion, everyone. Why not actually?
How many doses of flu vaccine should one receive?
All people vaccinated above the age of 9 years should receive a single dose.
Children up to the age of 9 that had been vaccinated against the flu in the past with two or more doses (in one season or several) should receive a single dose.
Children up to the age of 9 that had not been vaccinated against the flu in the past at all, or only received one dose are eligible for two doses that should be given at least 4 weeks apart.
When there’s a need for a second dose, it’s advisable to use the same vaccine and manufacturer. However, if this vaccine is not available it’s possible to use any flu vaccine given that it is not contra-indicated for another reason.
Where is the flu vaccine given?
The inactivated vaccine is given intra-muscularly in the thigh or arm depending on the age of the person vaccinated.
The live-attenuated vaccine is given as nasal spray.
Is it possible to reduce the pain when injecting this vaccine (or any other vaccine)?
Pain can be reduced in any shot or vaccine by distracting the child vaccinated.
The age from which this trick works, depends on the personality of the child and parents and the patience of the person giving the vaccine. I use a technique I call “funny coughs”.
I ask the child to look the other way and cough 7 times (or 10 or 13, whatever works).
If the child is calm and cooperative, the vaccine can be given with one of the coughs and the child will not feel getting the shot.
This technique can be used in all routine vaccinations with cooperative children above a certain age.
Can the influenza vaccine be given together with other vaccines?
Inactivated or live-attenuated vaccines can be given simultaneously with any other vaccine.
Concerning the Corona vaccine, it may be given with the flu vaccine at any time interval.
How effective is the flu vaccine?
This is the main Achilles’ heel of the flu vaccines.
Whether because the species of influenza change from one year to another, and the vaccine doesn’t always predict the exact species, or because the flu vaccines are not the most effective vaccines to begin with, the efficacy of the flu vaccine is low and everyone agrees does not suffice.
For example, the efficacy of preventing disease in all age groups in the USA in the season of 2018-2019 was only 47%.
There are populations in which the efficacy was higher (children between six and eighteen months of age, 61% efficacy) or lower (adults above the age of 50 years, only 24% efficacy).
So why bother and ramble on about the flu vaccine, and why get vaccinated at all when the efficacy is so expressly insufficient?
A. The efficacy changes from one year to another. Some years the efficacy is higher and reaches 70%.
B. People who have influenza after being vaccinated that season, have a milder disease compared with unvaccinated individuals (and this is also something).
And therefore, the main reason to get the flu vaccine is that we have no other way to defend ourselves of the disease and that if I were to suggest you to get ill 50% less often or less intensely with a disease that is utterly unpleasant and with a potential for complications, I think it would be right to take this offer with both hands.
I am hopeful that in the future someone will find a universal vaccine to all species, requiring only one administration in a lifetime.
Some families that I vaccinate at the beginning of the flu season approach me at the end and thank me for not getting sick at all during winter. This is great, but I always explain that it’s merely luck. The influenza vaccine reduces the prevalence of the flu, surely not of all other viruses that circulate in winter.
There are people who I vaccinated myself and did get the flu. Frustrating. To my relief, most of the cases had a milder disease than would without the vaccine.
Nevertheless, an emphasis on children. Due to the fact that children are at a high-risk group for infection and significant illness I think we all as parents, have an important role with compliance and recommendation of vaccinating children against the seasonal flu, including healthy children.
I wish us all an easy winter and plead you to get vaccinated starting in many countries in October 2022.