Baby vaccinations: why they matter, how to prepare and what reaction is normal

Updated August 15, 2026

Vaccination is one of the most reliable ways to protect a child from serious infections. A vaccine introduces the immune system to a germ in a safe form in advance, so that when it meets the real disease the body already knows how to fight it off.

Below: how it works, which reactions after a vaccination are normal and which need a doctor, how to prepare, and how real contraindications differ from common myths. The exact timing and list of vaccines depend on the country — your doctor sets them by the national schedule.

How vaccines work

A vaccine contains a weakened or killed germ, or just parts of it — enough for the immune system to "remember" the infection, but not enough to cause the disease. After a vaccination the body builds up protection, so that on meeting the real germ the disease either does not develop or passes mildly.

Vaccines follow a schedule and often several doses for a reason: a child's immunity builds up gradually, and the early months are the most dangerous for a number of infections. So it matters to vaccinate on time, not "when they are older" — it is exactly the early age that most needs protecting.

About the vaccination schedule

There is no single worldwide schedule: the set of vaccines and the timing are set by each country's national immunisation schedule, and it differs. The first vaccine is often given already in the maternity hospital. So we deliberately do not print specific dates and names here — your paediatrician will tell you the current schedule and what is due for your baby. If you have moved or were vaccinated in another country, bring all records of the vaccines given to the appointment.

Which reaction after a vaccination is normal

A mild reaction is a sign that the immune system is responding to the vaccine. In the first 1–2 days the following are common and not dangerous:

• Redness, slight swelling or tenderness at the injection site.
• A slight rise in temperature.
• Fussiness, sleepiness, a lower appetite for a day or two.

This usually settles on its own within 1–2 days. A cool clean compress on the injection site, more frequent feeds and a calm routine help the baby through it. A fever reducer (infant paracetamol or ibuprofen by age and weight) is given for a high fever or clear discomfort — on a doctor's advice, not "in advance as a precaution".

How to prepare for a vaccination

1. Health on the day. The baby should be well at the time of vaccination; a mild runny nose without fever is usually not a barrier, but the doctor decides at the check.
2. Tell the doctor what matters. Mention any severe allergy, a serious reaction to a previous dose, seizures, chronic illness, or if the baby takes medicines that affect immunity.
3. Bring the vaccination records. An immunisation record helps the doctor not to miss or double up a dose.
4. Calm and feeding. Feed the baby, hold them, distract them — contact with a parent helps during the jab; a calm adult calms the baby too.

Myths and facts about contraindications

True contraindications are few: a severe allergic reaction to a previous dose or a vaccine component, certain immune conditions for "live" vaccines, and an acute illness with a high fever (then the vaccine is briefly postponed until recovery). But the common reasons people give to "hold off" are most often not contraindications:

• A mild cold or a runny nose without fever — usually fine to vaccinate.
• Taking antibiotics in itself — not a reason to delay.
• Prematurity — such babies are, on the contrary, important to protect on time.
• Allergy, eczema or "dysbiosis" in general — not a contraindication to the schedule.
• The idea of "waiting until they are bigger and stronger" is harmful: delaying leaves the child unprotected in exactly the most vulnerable period.

How to keep track of the schedule

There are many vaccinations in the first years, on set dates and in several doses, and it is hard to hold in your head. Noting what was done and when, and how the baby coped with each vaccine, means you will not miss a date or repeat a dose, and at the appointment you can say exactly whether there was a reaction to the previous one. That is easier and more reliable than piecing it together from scraps of paper and memory.

Frequently asked questions

This article is for general information and does not replace medical advice. Only a doctor sets the vaccination schedule, indications and contraindications, according to your country's national schedule and your child's condition. Make all vaccination decisions together with your own paediatrician.