We’ve talked about how to prepare for immunization appointments but what about how to help support and care for your child after? The good thing is that immunizations are usually pretty low key – so there isn’t too much you need to do after, but here are a few tips for the management of some potential issues and what to look out for/when to call your doctor or head to emerge.
Dislcaimer: this is not medical advice. This blog is for informational purposes only and should not be interpreted as such. Please seek medical advice from your trusted healthcare provider.
Fever after immunization
It is not uncommon for a baby or child to develop a mild fever 24 to 48 hours after immunizations.
What is a mild fever? A common question I see, but also an area where there is a lot of misunderstanding – which is why I previously wrote a blog post on misconceptions around fevers.
Unfortunately, a “mild” fever and a “low-grade” fever are terms you see used but defined differently by different sources. The other issue is that a temperature reading varies depending on where it is taken from (I wrote about that a bit in this post).
If you’re going by more “official” definitions – the Center for Disease Control in the US defines a fever as a temperature above 38 degrees Celisus/104 degrees Fahrenheit. The Canadian Paediatric Society defines a fever as a temperature over 38 degrees Celsius/104 degrees Fahrenheit when taken via rectal or tympanic (ear) route, but a mouth or armpit reading has a lower threshold (37.5 degrees Celsius). Still not really a clear answer..
These ranges are also slightly different for children. Sigh. Oh and between people – everyone’s average can be slightly different. And based on the time of day. OMG.
I was able to find a definition for a high fever – >40 or 39.8 degrees Celsius (ear/rectum or armpit respectively). So, one can assume then that a mild fever is anything under this but still above the temperature cutoffs listed above (37.5-38 degrees Celsius, depending on route). Ok, that’s something.
What is a low-grade fever? Some professionals may not even consider this a fever – because like I said, so many things impact average temperature. You may just be a warmer person, or you could be measuring at a time of day when you will get a higher reading, and so on and so forth. There is actually no standard definition of a low-grade fever – but they’re apparently considered “higher than normal but not abnormal”, if you will. If you have concerns about your or your child’s temperature – call your local nurse line or provider’s office for clarification. They may also give you a hand out with what they consider to be a fever reading on a thermometer, and any follow up/after care that may be needed.
My personal opinion – again, not medical advice at all – is that a low grade fever is not any sort of fever but just a higher state of body temperature (or it could very well be a norm for some people). A mild fever, on the other hand, is a fever – but it’s not what is considered a high or “head right to the ER” (follow the guidance of your provider) type of fever.
Now that we have that kind of sorted out, let’s talk about management.
Like I said, a mild fever is not uncommon within the first 48 hours after an immunization. When you think about what an immunization is doing – it actually makes sense for a fever response to occur in some cases. Immunizations provide what we call active immunity – meaning the immune system is being triggered by the immunization which contains either a “killed” form of a virus or other disease, or a weakened version (these are often called live vaccines). When the immune system is triggered, it makes antibodies against the virus/disease. The idea is that the disease or virus can then can be recognized if encountered again and the antibodies against it can be released to fight it – ideally, preventing you from becoming sick or at least, making the illness more mild.
Your child would have a mild fever + perhaps feel hot to the touch or clammy. They may be irritable. They may want to nurse more if breastfed, or eat less if consuming solids. It is important to continue to either nurse them or give bottles; or offer water or things like crushed ice for hydration, when they have a fever.
FYI: it’s a good time to mention that if you’ve received a vaccine and breastfeed – although in some cases, some immunity may be passed on via antibodies in breast milk (this is called passive immunity), this is not a substitute for your child also receiving the vaccine. The amount of antibodies in breast milk is not equivalent to what is produced in response to an immunization.
Taking it easy after an immunization appointment can also be a good idea – don’t plan to do things after if possible. I like Friday appointments often if you work a 9-5 (and aren’t on maternity leave or have finished it) because it means you’re off the next day and sometimes the fever continues into 48 hours (or even just the irritability). Cuddle on the couch!
In terms of medication, you should follow the guidance of your healthcare provider for dosing and medications. Generally speaking, acetaminophen (Tylenol) is recommended under 6 months of age for this purpose, or ibuprofen (Motrin/Advil) after 6 months of age. I recently wrote posts on both these medications use in the childhood population (acetaminophen or ibuprofen) – but refer to your provider or a pharmacist for more specific information as this it not medical advice or intended to be interpreted as such. Notably these medications would be the Infant or Children’s type (liquid) for younger populations.
Some people want to wait to give medications with a mild fever – that is ok to do. It is good/normal for the body to have this response after an immunization anyways. However, if your child is uncomfortable – you can give it too. This is a personal choice (barring any contraindications based on medical conditions or from your provider).
If a high fever occurs, you should call your provider (if they’re open) and/or follow the guidance they gave you regarding this, or head to emerge if your child seems worse. You should also follow up on a fever lasting more than a day or two in this situation specifically. If you don’t know what to do – try calling a nurse line like Telehealth or use a virtual care option if this is accessible to you.
Redness, swelling or pain at the site
These are the most common reactions to occur after immunization in most populations – even adults! Most people do have some degree of pain or at least discomfort at the site of injections, some get redness and some get swelling. Some immunizations do cause more pain – which I’ve seen after administering a large variety of immunizations. For example, the tetanus combination shot is one that reportedly comes with a bit more pain and discomfort than some others.
In babies and young children, pain can be hard to communicate so this can be challenging to spot at times. Redness and swelling is also seen sometimes, but that’s easier to spot. If your child is experiencing pain – this can be demonstrated by pain to touch or general irritability, the above medication recommendations still stand (again – follow dosing guidelines from your provider or pharmacist, they are based on weight – and also follow the medication schedules for when to give it). You can also try non-pharmaceutical approaches like a cool cloth on the site of injection, skin to skin or cuddling, or nursing your baby if applicable. These will also help with swelling.
Sometimes what is called a nodule, or a small bump, might form at an injection site. There is not normally any treatment needed for these – monitor it but it should go away on its own over time (sometimes this can be quite a bit of time!). Redness would also go away in a day or two normally.
There is sometimes a rash that appears after the MMR or varicella (or combination) vaccines. Both MMR and Varicella are live vaccinations (weakened). A rash can appear with both and usually resolves in several days. With a varicella rash, there may be a risk for spread to those who do not have antibodies – so CDC recommends avoiding contact with infants and other immune compromised people until the rash is gone. If the rash is caused by varicella, it will appear chicken pox-like (watery blisters) but it should not be excessive or spread – in that case, you should contact your provider. You should also contact your provider if you have any concerns regarding a rash – ideally, the risk for rash should be mentioned at the appointments where these vaccines are administered. Generally – the rash is harmless and resolves quickly.
Severe or anaphylactic reactions to immunizations are not common. And it isn’t really something you’d worry about at home – your office or clinic where your child receives the immunizations should ask you to stay for at least 15 minutes after to monitor for a reaction. Children receiving immunizations at school should also be monitored for this amount of time. Allergic reactions can be treated and nurses and healthcare providers are trained to monitor for & respond to these reactions.
A note on Rotavirus
Some children may develop vomiting or diarrhea after this oral immunization. I spoke more about it in this post on the 2 month (and 4/6 month) appointments. The biggest risk with this is dehydration, so keeping up with breastfeeding or bottles is important. Contact your healthcare professional for further guidance re: additional fluids and if they are appropriate. Vomiting or diarrhea that is ongoing should be followed up on with your healthcare provider.
Uncommonly, intussusception can occur after this immunization which is a form of intestinal blockage. Babies may appear pale, vomit or experience pain. An ER visit would be needed and there is usually no longer term impact if treated.
For you – the parents – make sure you are washing your hands after diaper changes for ~2 weeks after this one is given! The virus may shed in your baby’s poop. Those with a weakened immune system should avoid doing diaper changes for 10-14 days.
What about irritability?
This is really probably the most common after effect of immunizations – but it is related to either pain or fever, usually. So follow the guidance your provider gives you for these two things and read the sections above for additional information.
As I mentioned before – avoiding scheduling anything else on the same day as an immunization is a good idea if you anticipate irritability! Stay home and cuddle if you can.
After care for immunizations is usually pretty straight forward. Symptoms that do appear should be short lived and easily managed. As always, if you’re worried or have concerns – call your provider, nurse line or similar resource. As I mentioned a few times – providers will often give you follow up or after care information at these appointments, so it is important to follow their guidance first!