What parents need to know about vaccination and side effects

Dr Sam Hay gets real about kids and vaccination, answering all the questions parents often ask.

Are you afraid of side effects from vaccines? Image: iStock

Like all great partnerships in life - Queen Elizabeth and Prince Philip, Laurel and Hardy, Barbie and Ken, Charlene and Scott, vaccines go hand-in-hand with side effects.  

You just can’t have one without the other; and in simple terms, having a side effect from a vaccination is not actually a bad thing - it tells us the vaccine is working.

Side effects get labeled in the medical world as ‘adverse events’ - and this term gets some of us a little spooked. When someone hears a solid medical term like ‘adverse event’, it immediately sounds scary - so that must mean there’s an ‘allergy’ involved. And allergy means anaphylaxis, and that’s bad. Which then means all vaccines are BAD!

And if an influencer tells me all of this - then it must be true…. Surely the anti-vaxxers can’t be right!?! 

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Are you afraid of side effects from vaccines? Image: iStock

Local skin reactions after vaccination

Over 80% of the time, that's basically every vaccine every time, there will be some sort of reaction at the site of the needle injection. 

• Swelling
• Redness
• Pain
• Soreness when moving the arm

The reaction is caused by a simple local inflammatory response that could occur to any noxious foreign event: a splinter, insect bite, or pin prick to name a few. With vaccinations, severity varies, but will usually be mild and won't stop anyone in the family from doing anything. Only occasionally will symptoms be bad enough to justify dad skipping washing-up duties.

Kids should be reassured that their arm will be better the next day; gym junkies can definitely train; and more intrusive symptoms could be treated with ice packs or simple analgesia like paracetamol or ibuprofen.

Severe local swelling

Severe swelling involving nearly the entire upper arm can occur once or twice every hundred injections, even in kids. It usually comes up in the first two or three days, and settles in a week. Basic pain relief and ice are all that's needed, and as it is often mistaken for cellulitis, you may need a check with your doctor.

Fevers, aches, and pains after vaccination

Our body battles infections by ramping up the immune system, resulting in aches, pains, fevers, headaches, and general miserableness. When we use a vaccine, we are in fact trying to do the same thing - prime and stimulate the immune system in preparation for future infections. 

So it stands to reason, that for a day or so after a vaccination you’ll get:

• Fever
• Body aches (joints and muscles)
• Headaches
• Nausea
• General tiredness and feeling unwell.
• Irritable or unsettled young kids; or maybe kids sleep a little longer

Again, this is a good sign that the vaccine is doing its job, and it’s not a sign of allergy or danger. Most people get very little, none, or mild symptoms; only occasionally will they be intrusive or moderate. But don’t be alarmed if you or your kids don’t get any of these symptoms - it’s often completely random who does and doesn’t get them.

Generally rest, fluids, and basic analgesics are all that are required - often only a single dose.

Rarely, symptoms can flare several days after the vaccination. Checking in with your doctor will help distinguish vaccine side effects from other common causes of these symptoms such as colds and flus. 

Bottom line, whilst annoying, no matter how severe, these symptoms don’t stop you from having future repeat shots.

Do you need to give paracetamol before a vaccination? 

In general, no - it is not necessary. However, the Meningococcal B vaccination is associated with a higher rate of fever at around 50%.

Parents are encouraged to administer a dose of paracetamol prior to each vaccination which is extremely effective, and aimed at reducing the potential risk of febrile seizure. Discuss this further with your doctor.

Hypersensitivity - Allergic Reactions

Every vaccine and every vaccine ingredient has the potential to cause a hypersensitivity or allergic reaction in a patient. That reaction could be immediate, or delayed; and includes a huge plethora of symptoms all over the body, from mild rashes through to full-blown anaphylaxis.

The most common symptoms and signs associated with both immediate and delayed reactions are:

• Skin: itching, hives, flushing, and angioedema.
• Cardiovascular System: fast pulse, palpitations, faintness, low blood pressure, losing consciousness.
• Respiratory System: Nasal congestion, wheezing, coughing, throat tightness, change in voice, difficulty breathing.

Immediate Reactions

In general, it’s the immediate reactions that get the greatest attention. They occur within the first hour and are generally mediated by specific IgE reactions - which means they carry a risk of future anaphylaxis if a patient is exposed.

Anaphylaxis

 Anaphylaxis is the most severe form of immediate IgE reaction, resulting in complete body shutdown. It can be swift, and it can be fatal. But thankfully it’s rare.

In fact, anaphylactic reactions occur in less than 1 in a million vaccinations.

When anaphylaxis occurs, it usually sets in within 30 minutes from the time of injection, and mostly in the first 5-10 minutes - that’s why your doctor asks you to hang around for a while after your needles.

RELATED: Does my child need the flu vaccine?

RELATED: ‘My toddler’s vaccine reaction was scary – not vaccinating would be scarier’

It's common for children to get a sore arm after a vaccination. Image: iStock

Delayed Reactions

Appear several hours to days after vaccination. Whilst they may be allergy driven, they also arise from many different non-allergic mechanisms in the body. Many of these reactions will still need assessment by an immunologist, but they very rarely lead to future issues.

The most common non-allergic delayed reactions are seen with the MMR and Chicken Pox vaccinations.

Measles, Mumps, Rubella

The MMR vaccine is classically associated with a fine rash in about 5% of cases that can pop up, even two weeks after the vaccine.  It’s not contagious, occurs mostly after the first dose, and doesn’t mean you can’t have future doses.

Varicella (Chicken Pox)

Whilst about 3% can get a handful of chicken pox-looking blisters around the injection site within a few days of the injection; up to 5% can get a more widespread mild rash up to a month later. Once again it’s not contagious, which means kids can go to school. 

Anxiety, fits, and faints: the great mimickers

It’s no secret that many people hate needles, especially adolescent kids. Some suffer a simple vasovagal faint, whilst many work themselves up into incredible frenzies with an acute panic attack.

The problem is that it can often be hard to tell the difference between a panic attack, vaso-vagal faint, and an anaphylactic reaction. That’s why it’s important for everyone to remain calm, for the medical team to get in and assess patients carefully - because if there’s a true allergic reaction like anaphylaxis going on then specific signs will be found, and critical treatment needs to be given.

If you know you or your family member is a fainter - then please ask to lie down for your next needle!

What do you do if you suspect an allergy to a vaccine?

Every unusual reaction to vaccination needs careful consideration with your family doctor.

Symptoms that fit more with allergic or hypersensitivity reactions, especially ‘immediate’ ones, will need referral to an immunologist for assessment. The immunologist may conduct patch tests or challenge tests to determine the level of reaction, and the presence of true allergy. 

True vaccine allergy is unbelievably rare - found to be less than 1 in a million cases. This means that the significant majority of kids can be safely vaccinated into the future, despite suffering side effects or reactions following a vaccination.

The last word: vaccines and autism

Never, ever, EVER have vaccines caused autism!

This absolute MYTH centers around a shonk of a doctor who released atrocious research linking the MMR vaccine to Autism. The research has been retracted and the link disproved countless times, but unfortunately the issue continues to gain unfounded attention.

Thimerosal exposure

Thimerosal is a preservative used in a number of vaccinations and widely touted by the anti-vax brigade to be linked to mercury-related neurological effects and autism. Numerous research refute these claims.

Aluminium exposure

Aluminium is also added to many vaccines, and has been falsely linked to complications, with cumulative doses from all childhood vaccinations believed to reach dangerous levels. Once again, no evidence for this has been found from extensive research.

Bottom line - talk to your doctor - not your favourite social media influencer!

Originally published as What parents need to know about vaccination and side effects