Fri | Aug 7, 2020

The truth about flu vaccines

Published:Wednesday | February 20, 2019 | 12:00 AM
Dr Yohann White

No matter how fit and in tip-top shape I think I am, once I pass through an airport, I get the sniffles.

However, you don’t even need to be travelling to be exposed to the flu. With the increasing ease of travel, the flu comes to you. Every so often, a major strain of flu comes about, leaving a trail of death and sickness in its path. Nearly a hundred years ago, the Spanish flu killed more than 50 million people – that’s 20 times the population of Jamaica.

The World Health Organization (WHO) has estimated that the 1950s Asian flu killed about two million people worldwide. In just 2009, a new strain of flu infected at least 10 million people, and over 100,000 people died. Fortunately, deadly strains like these come about only a couple times in a 100-year span. They come about when flu strains that affect animals like pigs and ducks cross with human flu strains.


What is more common is the seasonal flu. Flu can cause you to have a fever and sore throat. Unlike the common cold where you have a runny nose and cough, but you can keep up with your normal activities, the flu makes you feel awful.

Flu may give you a headache, muscle pains, joint pains, and you feel tired and weak, and have no appetite. Really bad cases not only affect the lining of your windpipes or airways, but the virus may get deep down into your lung tissues, causing them to become inflamed and soggy with fluids and pus, and interfere with your breathing. The flu can also get into the brain. The flu can be deadly.

Anyone can get the flu, but persons with a weak immune system or certain medical conditions like asthma, diabetes or ‘sugar’, and kidney disease may get the flu more easily and also have more serious complications.

Fortunately, there are ways we can protect ourselves from seasonal flu. Washing your hands often and covering your mouth when you cough or sneeze are effective in minimising the spread of flu.


We have a flu vaccine. Now, the flu vaccine actually contains an inactivated form of the flu virus in a very small amount. We grow the virus in chicken eggs. The chicken egg is like a mini-farm for cute little viruses.

Interesting fact: It takes about two eggs to grow up enough virus for one dose of vaccine. More important, though, if you have an allergy to eggs, you should tell your doctor.

And the flu vaccine does NOT give you the flu. In the manufacturing process, once the viruses are grown up in the chicken eggs and harvested, they are shredded into tiny bits.

We are interested in the envelope shield covering the viruses because it has some little spikes sticking off of it. The virus uses these spikes to attach itself to the lining of your airways and cause disease. Because the spikes are sticking out, when the flu virus tries to get into your body, the spikes are the first things your immune system sees.

It’s these little spikes that form the key ingredient in the vaccine, as it trains your immune system to easily recognise and protect itself from the actual flu virus.

We are interested in the envelope shield covering the viruses because it has some little spikes sticking off of it. The virus uses these spikes to attach itself to the lining of your airways and cause disease.

Of course, we can get reactions to many other medications and even non-medications like make-up or certain foods like shellfish or peanuts, etc. Some persons can be sensitive or allergic to certain things in the vaccine like the antibiotics used to keep the chicken eggs and manufacturing processes free of germs. Tiny traces may get into the vaccine. Other reactions include redness at the site of injection. Some persons may even get a mild fever, and this is really just showing that hey, this vaccine is working and your body is recognising the vaccine and learning how to mount a fight for the next time it sees a real flu virus.


And yes, the flu vaccine may contain trace amounts of formaldehyde, an organic substance used to inactivate or kill the flu virus so it doesn’t harm you when it’s used to make vaccines.

But did you know that your body naturally produces formaldehyde? It does. Even in newborn babies. Our bodies naturally produce formaldehyde when it is making amino acids – the building blocks of proteins that make up your muscles, for example.

The US Food and Drug Administration (FDA) has stated that the amount of formaldehyde in a dose of vaccine hasn’t even reached one per cent of the total amount of formaldehyde naturally found in newborns. As you get older, your body naturally produces even more formaldehyde. It is also found in other vaccines like the vaccines you received to protect you from polio and lockjaw.

There is a trace amount of mercury in bulk flu vaccines (multiple doses from a larger bottle), but not in the single-dose ones in the pre-filled syringes that I like to use, for example. Being exposed to mercury, such as in the soil or in certain older paints in some buildings, can have a negative effect on your health. And since patients are reading about these things all over the Internet, it’s important that they hear what healthcare providers have to say about it.

Mercury can build up in fish that we eat or it can be in the environment. In fact, in a scientific study published in the Neurotoxicity Research journal, measuring mercury levels in the blood of Jamaican children, it seems we have a lot more to be concerned about the mercury levels in seafoods, including sardine, mackerel and saltwater fish.

Fortunately, it’s a different kind of mercury that’s used as a preservative in some vaccines, and the body readily clears this from the body.


Remember those little spikes on the surface of the flu virus? Well, because they are the first parts of the virus that your immune system will see, the flu has a way of changing up these spikes. These changes mean that your body is seeing this version of the virus for the first time, and would not have had the chance to build up protection against it unless you had received a vaccine before.

Throughout the year, the WHO collects samples from all over the world to keep track of what new flu strains are circulating. The WHO uses this information to decide what flu strains should be included in the vaccine. Hence, a new flu vaccine is made available every year to protect you from new strains.

Because we are used to the idea of getting one or two vaccines for other diseases once or so while growing up, the idea of requiring the same vaccine every year surprises some persons. But there is good reason behind it. Scientists are now working on developing a ‘universal vaccine’ based on another part of the virus other than the spikes – so that hopefully, one vaccine will protect you for years.


This is a very common question. Our idea of a vaccine is that you get it as a child growing up, and you just don’t get polio or lockjaw. But even after getting the flu vaccine, you can still catch the flu. However, someone who has received the flu vaccine usually has milder symptoms and recovers faster than someone who had not received the flu vaccine.

The flu vaccine cuts the chance of your requiring hospitalisation by half! And if you do happen to require admission to a hospital for flu, you are far less likely to have to be placed on a ventilator or breathing machine.

There is a lot of misinformation out there about vaccines in general, but perhaps especially for the flu vaccine. With the ease of travel these days, a really terrible flu from anywhere in the world could reach our shores.

Flu is of particular concern, because we have seen its devastating effects. It is my hope that we will develop a culture of awareness and preparation, and getting your flu vaccine every year is a great start.

Dr Yohann White, MBBS, PhD, DTMH, is medical director at Para Caribe Consulting Medical Doctors. Email and