A VAXING QUESTION
Tossing up whether it’s worth getting a flu shot this year? Worried it’s not right for you as you are pregnant or have an underlying health condition? Here’s what you need to know.
Should you have a flu shot this year? We examine all t the pros and cons.
It’s the season of sniffles in the southern hemisphere and while the world is waiting for an inoculation against COVID-19, vaccines are at the forefront of everyone’s minds.
Medical authorities are urging us to have a flu shot this year to help keep hospital beds clear for coronavirus cases and to prevent people from contracting both illnesses simultaneously. The New Zealand public are taking up the suggestion in high numbers, with more than 600,000 flu vaccines administered by late April this year – more than double the amount by the same time in 2019.
But are these vaccines really the most effective way to fight the flu? Could they do more harm than good to some individuals? And for healthy individuals, is there any point in having one at all?
COLD OR FLU?
The words are often used interchangeably, but what actually is the difference between a cold and the flu? A cold is one of roughly 200 viruses that commonly cause a sore throat, sneezing, runny nose, headache and coughing. The flu is a much more severe viral infection that shares several of its symptoms with colds, often accompanied by aches and pains, fatigue and fever, which aren’t usually present when you have a cold.
Although many people believe catching a cold or the flu can be directly caused by winter’s chilly conditions, scientists believe it’s actually our tendency to huddle together indoors, encouraging the spread by putting us in closer contact with each other.
Recommended treatments for both illnesses include bed rest, a healthy diet, plenty of fluids, keeping warm and using throat lozenges for a sore throat. Groups such as the elderly, pregnant women, Māori and Pacific Island people and those with pre-existing medical conditions are particularly vulnerable to contracting the flu.
The flu tends to target the lower respiratory tract (i.e. the lungs), while colds usually content themselves with infecting the upper respiratory tract, causing milder symptoms. In the meantime, the damage to your lungs from the flu, in particular, leaves your body susceptible to both viral pneumonia, which progresses quite quickly after the onset of illness, and bacterial pneumonia, which can take about one to three weeks to develop. These infections, GP Phil Humphris explains, have a devastating effect on your body. “The infection in the lungs actually damages the lung tissue. Where normally it would absorb oxygen, it just can’t perform its normal function, so you can’t breathe and eventually it leads to the shutdown of other bodily organs, requiring intensive care and supportive care.”
Once the flu gains the upper hand, there’s not much medical professionals can do to attack the virus head on. The best treatment they can offer is to shore up your body while it’s locked in battle.
“There are no drugs we have to kill viruses like that,” says Humphris. “The medical treatment, even in advanced intensive care, is really focused on supporting the body through it, providing oxygen, providing fluid, providing medications, other ways to support the body, but there’s nothing directly that kills the flu virus.”
There are prescription medicines such as Tamiflu that reduce symptoms of the flu, but they’re only really effective if taken within 48 hours of onset of symptoms, or in the case of immunocompromised patients, they might be worth taking pre-emptively.
Each year, scientists produce a vaccine aimed at reducing the impact of the flu season by inoculating the public against the most likely strains to be afflicting us. The vaccine works by exposing the body to a dead version of the virus.
The body works out how to handle that virus in case it ever meets it again and stores those combat tactics away for future use.
“The body stores that information, so it is a teaching process,” says Humphris. “Those antibodies are made in very small numbers and kept in some of the cells of the immune system.
“Then, if that particular virus enters the body, normally through the respiratory tracts – nose, mouth, eyes, etc – the body can recognise it and very quickly produce many, many copies of that antibody and provoke the immune response that enables it to fight it off.”
VACCINE EFFECTIVENESS
Several factors influence the effectiveness of the flu vaccine. Predominant among them are whether scientists can correctly predict which variations of the flu virus will reach our shores during the peak winter season, whether these strains have changed significantly in the meantime, and the effectiveness of the particular vaccine we’ve developed to combat them.
As the formulation of these vaccines are created many months before they are injected into patients, there’s a certain amount of educated guesswork that goes into forecasting which flu viruses will be around in a particular season.
Professor Ian Barr from the Peter Doherty Institute for Infection and Immunity says the vaccine doesn’t come with an ironclad guarantee of immunity. “It’s not a wonder vaccine – in a good year, you would expect something like 60 per cent effectiveness. In a bad year, for certain components it could be lower.” Sixty per cent might seem low, but Barr points out there are few alternatives that have much success in protecting you.
“There are not a lot of other things you can do really – wearing a mask 24/7 is one option, but that’s still not perfect either,” he says. “You can take antiviral drugs, but you have to take them continually to have the same effect as a good vaccination, so there are very few other things you can do that will give you the same benefits.”
“ONCE THE FLU GAINS THE UPPER HAND, THERE’S NOT MUCH DOCTORS CAN DO.”
Another important factor which influences a vaccine’s effectiveness on an individual level is a person’s age – the body’s immune system weakens as we get older.
Some people, such as the elderly, either don’t develop much of an immune response when they are vaccinated, or can’t be vaccinated due to health concerns or (rare) allergic reactions. This is where herd immunity becomes useful in reducing the spread to people whose defences are down against this type of illness, according to immunologist Professor Cassandra Berry from Murdoch University.
“The severely immunecompromised and those with allergies or severe side effects to previous flu vaccinations may be medically advised not to receive the flu vaccine as there is a risk of anaphylaxis and rare complications,” says Berry.
“Herd immunity allows protection of vulnerable people in a community simply by preventing the virus from transmitting and spreading through resistant individuals to reach the susceptible. The higher the percentage of vaccinated, immune people in a community, the stronger the protection of the vulnerable few individuals.”
The vaccine is also generally safe to take for patients who have a compromised immune system, as it contains a dead version of the virus and does not weaken their immune system. It may, however, not be recommended as people with certain types of illnesses and conditions might have a reduced ability for their body to develop a strong, lasting immunity when given the dose.
THE DOWNSIDES
Most of the time, the side effects of having a flu shot are on the mild side and typically only last a day or two. These include fever, tiredness, muscle pain, headache, a slightly elevated temperature, and soreness around the entry point of the injection. Severe reactions, on the other hand, are highly unlikely to crop up, but can lead to serious and potentially fatal symptoms.
“The more severe reactions are extremely rare – I’ve certainly never seen one,” says Humphris. “The rare ones are really more the allergic reactions. You can get hives or swelling around the mouth and lips or it can provoke a worsening of asthma or a full-on anaphylaxis allergic response.”
The most common of the rare and severe kinds of complications is Guillain-Barré syndrome, which affects the body in a similar way to chronic fatigue. The illness has about one or two new cases per 100,000 people each year. These are mainly caused by gastro-intestinal or respiratory infections, including influenza, but there is evidence showing the flu vaccine itself can also cause it at a rate of one case per one million vaccine doses.
In addition, there is the cost of the vaccine if you don’t qualify for a free one, time and inconvenience to visit the doctor or pharmacy to have a vaccine administered.
If you experience side effects, you might also need to take a day or two off from work or your usual activities to recover.
MAKING IT MANDATORY
There are those in the community who reject vaccines as being ineffective and potentially dangerous, questioning the motives of the scientists, pharmaceutical companies, medical organisations, and governments who promote them.
This is not a new phenomenon – since vaccination became widespread in the 1800s for smallpox, there have always been people who vigorously opposed it.
There have been moves in the intervening years to make vaccinations for various illnesses compulsory, but it has remained a contentious topic.
In more recent years, legislators have attempted to link inoculation against illnesses to eligibility for tax benefits and various types of employment.
Those against this type of action argue that it violates a person’s civil liberties and right to choose what happens to their own body. Those in favour argue it protects those in high-exposure, vital jobs, as well as the people being cared for by them.
“People in certain jobs, especially during the current COVID-19 pandemic, in positions of healthcare and essential services would benefit from flu vaccination as they are at high risk of exposure. Also, those working in aged-care homes and caring for the vulnerable (homeless and elderly) would benefit from vaccination. High levels of vaccination would allow these people to sustain their critical roles in dealing with the pandemic crisis,” says Berry.
REDUCING YOUR RISK
So why would you have the vaccine if you’re a strong, healthy person and you’re confident your body could fight off whatever comes its way? One reason is that you may have underlying illnesses you’re not aware of that could undermine your body’s response to the flu virus.
“People might have conditions such as chronic heart or lung conditions, which they may or may not even be aware of that might impact their outcomes from being infected with influenza,” says Barr. “The first time they know about it is when they end up in hospital.”
Other common conditions such as diabetes, asthma and being overweight are also linked to poorer outcomes if you contract the flu. For those who are incorrect in assuming they’re free from these types of illnesses, failing to have a flu vaccine puts their body behind the eight ball in trying to fend off the illness.
“Even if you are a fit and healthy person, your immune system may be naïve and have never seen the attacking flu virus strain,” says Berry.
“Without prior immunity, the race between the immune response and the virus replication may be won by the virus.
“Flu viruses are very fast and rapidly replicate in about six hours, while our immune cells need about seven to 10 days to generate a clonal army in specific combat against the virus.
“By this time, we may feel very unwell, develop severe disease and spread it to others who are more susceptible.”