The importance of flu protection and why doctors keep talking about it

You must be thinking … “The flu again?” We have had an article every year about the flu, the flu vaccine and all that there is to know about flu protection.
Well, the fact is that we must repeat, repeat, repeat, and update, update, update in an attempt to reach as many people as we can.

Even if you think you know all about the flu, please read this and if you were one of those who did not consider the importance of having a flu vaccine last year, think again.

Do it for your own health and for the health of the rest of the people within our world.

(WHO/Europe influenza control and other respiratory pathogens)
“Influenza is an acute viral infection that spreads easily from person to person in any age group and can cause serious complications in certain risk groups. In addition to seasonal epidemics, influenza pandemics can occur when a new influenza virus subtype emerges or when an animal influenza virus begins to spread among humans.”

Influenza infection occurs worldwide. In the WHO European Region, annual influenza epidemics usually occur during autumn and winter and can infect up to 20% of the population.

Seasonal influenza can cause substantial mortality. A 2017 study found that, worldwide, up to 650,000 people die of influenza-associated respiratory disease each year and up to 72,000 of these deaths occur in the European region.

Influenza vaccines are safe and effective, and annual vaccination is the most effective measure for preventing influenza and reducing the impact of epidemics.
There are two main types of seasonal influenza viruses that cause illness in humans: type A and type B.

Due to the constantly evolving nature of influenza viruses, the compositions of viruses in influenza vaccines need to be revised periodically. WHO updates recommendations for the composition of the influenza vaccine twice a year: in February for the northern hemisphere and in September for the southern hemisphere.

The recommendations are based on viruses detected and characterised by member states through surveillance and are used by the national vaccine regulatory agencies and the pharmaceutical companies to develop, produce and license influenza vaccines.

Is influenza really that serious?
Influenza can cause severe disease and death, especially in older people, young children, pregnant women and people with long-term health conditions such as diabetes, heart disease or chronic obstructive pulmonary disorder. As influenza vaccination coverage remains low in many countries, deaths can unfortunately be expected every winter season in these at-risk groups.

Who needs the influenza vaccine?
Anyone can catch influenza, but certain groups have a higher risk of developing severe disease. WHO recommends vaccinating older individuals, young children, pregnant women and people with underlying health conditions. These are the groups most likely to suffer serious complications from influenza, which is why most countries prioritise them for vaccination. Health-care workers need to be vaccinated for their own protection and to reduce the risk of infecting vulnerable patients with the virus.

How effective is the influenza vaccine?
The influenza vaccine is the best tool we have for preventing influenza and reducing the risk of serious complications and even death. The effectiveness of the vaccine can vary from year to year, depending on the types of influenza viruses circulating and how well these match the vaccine.

It also depends on the health status and age of the person vaccinated, as well as time since vaccination.

On average, the vaccine prevents around 60% of infections in healthy adults aged 18–64. Influenza vaccines become effective about 14 days after vaccination.

Can people catch influenza from being vaccinated?
It is impossible to get influenza from the injected vaccine because it does not contain live viruses.

Why do people need to be vaccinated every winter?
Influenza viruses constantly change and different strains can circulate each year. In addition, immunity decreases over time. Seasonal influenza vaccines are updated each year to provide the highest possible protection by matching the circulating viruses.

At what point in the year is it too late to be vaccinated?
It is best to get vaccinated before the influenza season starts. Influenza vaccination campaigns usually take place in October and November, before influenza begins circulating. It is never too late to be vaccinated if influenza is still circulating; vaccination increases the chances of being protected from infection and reduces severe consequences from the disease.

Is the influenza vaccine safe?
Seasonal influenza vaccines have been in use for more than 50 years. They have been administered to millions of people and have a good safety record. Every year, national medicine regulatory authorities carefully examine each influenza vaccine before it is licensed. Systems are in place to monitor and investigate any reports of adverse events following influenza immunization.

We cannot predict how bad this year’s flu season will be
Part of the problem with predicting the influenza season is that we talk about one season, but four distinct influenza viruses cause clinically important illness in humans.

Flu viruses are continually mutating in nature, and so any immunity acquired from a previous infection or vaccine may provide little protection against the viruses that will circulate in the next season.

There is also little cross-immunity. Infection with A(H1N1), for example, will not necessarily protect you against A(H3N2). It is even possible, though unlikely, to be infected with two viruses at the same time or in close succession.

Herd immunity
Also called herd effect, community immunity, population immunity, or social immunity is a form of indirect protection from infectious disease that occurs when a large percentage of a population has become immune to an infection, thereby providing a measure of protection for individuals who are not immune.

In a population in which a large number of individuals are immune, chains of infection are likely to be disrupted, which stops or slows the spread of disease.

The greater the proportion of individuals in a community who are immune, the smaller the probability that those who are not immune will come into contact with an infectious individual.

Individual immunity can be gained by recovering from an infection or through vaccination.

Some individuals cannot become immune due to medical reasons and in this group herd immunity is an important method of protection.

The term herd immunity was first used in 1923. Mass vaccination to induce herd immunity has become common and proved successful in preventing the spread of many infectious diseases. Opposition to vaccination has posed a challenge to herd immunity, allowing preventable diseases to persist in or return to communities that have inadequate vaccination rates.

This is why flu vaccination is so important for everybody!

Best health wishes,
Maria Alice

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Dr Maria Alice is a consultant in General and Family Medicine. General Manager/Medical Director – Luzdoc International Medical Service. Medical Director – Grupo Hospital Particular do Algarve/ Hospital S. Gonçalo de Lagos