When to vaccinate your child: the full schedule and answers to parents’ questions

The first vaccines are given in the maternity hospital (hepatitis B and BCG), and the immunisation process continues until adulthood according to the National Immunisation Schedule. Regular vaccination protects your child against 14 serious infectious diseases.

Key points:

• First vaccination: 0-24 hours after birth
• Most intensive period: 0-18 months (9 mandatory vaccines)
• Last mandatory immunisation: age 12 (HPV for girls, DTaP booster for boys)

When does vaccination start, and why so early?

A baby’s first vaccination takes place in the first 24 hours after birth in the maternity hospital, when the vaccines against hepatitis B and tuberculosis (BCG) are given. This early start is critical, as newborns are most vulnerable to infection in the first days of life.

The hepatitis B vaccine is given immediately after birth because the virus can be passed from mother to baby during delivery. According to the World Health Organization, early immunisation within the first 24 hours significantly reduces the risk of chronic hepatitis B infection. The BCG vaccine against tuberculosis is given between days 0 and 5, as tuberculosis remains a serious health problem in Bulgaria and Eastern Europe.

The immunisation schedule in Bulgaria is structured so that the most intensive period of vaccination is between birth and 18 months, when the child receives a total of 9 different vaccines in multiple doses. Boosters then follow at key ages up to 12 years.

What does the full immunisation schedule in Bulgaria look like?

The National Immunisation Schedule sets out 14 mandatory vaccines that protect children from serious infectious diseases. Bulgaria follows the World Health Organization’s recommendations for mandatory childhood immunisation.

Schedule of mandatory vaccines by age:

Why are these timings so important for a child’s health?

The immunisation schedule is not arbitrary: each vaccine is planned for the exact moment when the child most needs protection. The timings are based on three key factors.

First, the protection received from the mother wears off. Newborns receive antibodies from their mother through the placenta during pregnancy, but this protection fades 2-6 months after birth. Vaccines take over exactly when the mother’s antibodies are no longer enough for full protection.

Second, the child’s immune system is ready to respond effectively. A child’s immune system develops gradually in the first months of life. The vaccines at 2, 3 and 4 months are timed to the moments when the body can form an effective immune memory without being overloaded.

Third, the risk of disease is highest in exactly these periods. Whooping cough is most dangerous, and often fatal, for babies under 6 months. Pneumococcal infections peak in children aged 6-18 months. Measles most often affects children between 1 and 3 years. The schedule protects the child before they reach the age groups at highest risk.

What happens if we’re late with vaccination?

If you are late vaccinating your child, the consequences depend on how long the delay is and the type of vaccine. Children whose immunisation schedule isn’t followed have a significantly higher risk of severe complications from infectious diseases.

A delay of 1-2 weeks for a planned vaccination is usually not a problem, according to paediatric recommendations. The paediatrician can adapt the immunisation schedule without any loss of effectiveness or protection. In this case, it is important to contact your family doctor for a new date, but your child will not lose the protection from doses already given.

A delay of more than a month leaves the child unprotected for longer. Some vaccines, such as DTaP (diphtheria-tetanus-pertussis), require minimum intervals between doses for optimal effectiveness. Skipping these intervals can extend the whole immunisation schedule by several months and leave the child vulnerable during critical periods.

No vaccination at all significantly increases health risks. Unvaccinated children have a many times higher risk of diseases such as measles, whooping cough and other vaccine-preventable infections than regularly vaccinated children. In outbreaks, unvaccinated children are often the first to be infected.

When should we postpone a planned vaccination?

There are medically justified situations in which vaccination should be temporarily postponed for the child’s safety. According to medical recommendations, the following conditions require postponement.

Always postpone vaccination in case of:

• An acute infectious illness with a temperature above 38.5°C, as the vaccine may worsen the condition
• A severe allergic reaction (anaphylaxis) to a previous dose of the same vaccine
• Immune deficiency or treatment with immunosuppressive medicines: consult a paediatric immunologist
• Treatment with high doses of corticosteroids (more than 2 mg/kg per day for more than 14 days)

Do NOT postpone vaccination in these common situations:

• A mild cold with no temperature, or a temperature below 38°C
• Antibiotic treatment (unless the paediatrician specifically advises otherwise)
• Contact with a sick family member: vaccination may be even more urgent
• Mild stomach or bowel problems without dehydration
• Food allergies unrelated to the vaccine’s components

If you are unsure whether to postpone a vaccination, always consult your child’s paediatrician. Postponing without good reason leaves your child unprotected during critical periods.

What happens if a child has an allergic reaction to a vaccine?

Allergic reactions to vaccines in children are rare, but it is important for parents to know how to recognise them and how to respond. Severe allergic reactions (anaphylaxis) are extremely rare in childhood vaccination.

Mild allergic reactions include:

• Redness and mild swelling at the injection site (up to 5 cm across)
• A skin rash in the first 24-48 hours
• A slight temperature up to 38.5°C
• Irritability or restlessness

These reactions need no treatment and go away on their own within 2-3 days. Cold compresses on the injection site and paracetamol if needed are enough.

Moderate allergic reactions include:

• A widespread rash (hives) all over the body
• Swelling of the face or lips
• Vomiting or diarrhoea
• A temperature above 39°C

For moderate reactions, call the paediatrician immediately. They may prescribe antihistamines and assess whether the child needs to be seen in person.

A severe allergic reaction (anaphylaxis) requires emergency medical help:

• Difficulty breathing, wheezing or shortness of breath
• Swelling of the throat and tongue
• Pallor, cold skin, rapid pulse
• Loss of consciousness

Anaphylaxis usually appears within 15-30 minutes of vaccination, which is why paediatricians recommend that parents stay at the clinic for at least 30 minutes after every vaccination for observation.

In case of anaphylaxis, medical staff immediately give:

• Adrenaline (epinephrine) by intramuscular injection
• Oxygen therapy
• Antihistamines and corticosteroids
• Observation in hospital

If a child has had a severe allergic reaction to a particular vaccine, that vaccine is not given again. The paediatrician will consider alternatives or adapt the immunisation schedule.

How do we recognise side effects that need a doctor straight away?

Most side effects after vaccination are mild and temporary, but there are specific symptoms that require immediate medical advice. Parents need to know when to act urgently.

Call 112 immediately or go to an emergency department in case of:

Severe breathing problems:

• Shortness of breath, wheezing or difficulty breathing
• Blue lips or face (cyanosis)
• Rapid, shallow breathing

Neurological symptoms:

• Seizures or convulsions (with or without a temperature)
• An unresponsive, floppy child who cannot be woken
• A bulging soft spot (fontanelle) in babies
• Unusually intense or non-stop crying for more than 3 hours

Severe allergic reactions:

• Swelling of the face, lips, tongue or throat
• A widespread rash with swelling
• Cold, pale, clammy skin

Call your paediatrician the same day in case of:

A high or prolonged temperature:

• A temperature above 39.5°C in children over 3 months
• A temperature above 38°C in babies under 3 months (always a warning sign)
• A temperature above 38°C lasting more than 48 hours after vaccination

Local reactions that are getting worse:

• Redness or swelling at the injection site that is spreading
• Warm, painful swelling more than 10 cm across
• Pus coming from the injection site

Stomach and bowel symptoms:

• Vomiting more than 3 times in 6 hours
• Diarrhoea with blood
• Refusing food and fluids, with signs of dehydration

Changes in behaviour:

• Unusual lethargy: the child sleeps for more than 4 hours without waking after vaccination
• Irritability that doesn’t settle with the usual methods
• Refusing to feed for more than 8 hours

Normal side effects that do NOT need a doctor:

• A mild to moderate temperature (37.5-38.5°C) in the first 24-48 hours
• Redness of up to 5 cm around the injection site
• Irritability or tearfulness for 1-2 days
• Sleepiness for 24 hours after vaccination
• A slight loss of appetite

If in doubt, always call the paediatrician. It is better to check about a small problem than to wait for a serious symptom.

Why do some parents choose alternative vaccination schedules?

A small number of parents choose to modify the standard immunisation schedule by splitting up vaccines or extending the intervals between doses.

Main reasons for choosing an alternative schedule:

Concerns about “overloading” the immune system are the most common reason. Some parents believe that giving several vaccines at once is too much for a child’s immunity. According to immunologists, however, a child’s immune system can process thousands of antigens at the same time; modern vaccines contain only 10-20 antigens, a tiny fraction of the immune system’s capacity.

A family history of allergies or autoimmune diseases leads some parents to prefer a slower schedule with more time for observation between vaccines. For children at high risk of allergic reactions, the paediatrician may indeed recommend a modified schedule, with higher-risk vaccines given separately.

A negative personal experience after an older sibling’s vaccination motivates some parents to change their approach with their next children. If a previous child had a strong reaction to a particular vaccine, the fear is understandable, although statistically a repeat is unlikely.

Information from social media and alternative health sources plays a role for some parents. Distrust of conventional medicine and a preference for “natural” methods can lead to a decision to vaccinate minimally or late.

What are the risks of alternative schedules?

Children following alternative schedules have a higher risk of catching vaccine-preventable diseases than those on the standard schedule.

Longer intervals between doses leave the child unprotected for longer. For example, splitting the DTaP vaccine into three separate visits instead of one combined dose means the child is not fully protected against whooping cough, diphtheria and tetanus for an extra 4-6 months. During this time, the risk of whooping cough (especially dangerous for babies) remains high.

A “spread-out” schedule does not reduce side effects. Paediatric observations show that the frequency and severity of side effects don’t change when vaccines are separated. The child simply goes through more visits and more injections, with no additional benefit.

Missed appointments and incomplete immunisation become more common. The more visits needed, the more likely parents are to miss one because of life circumstances. Children on a modified schedule are more likely to remain incompletely immunised at 24 months.

If you choose an alternative schedule, work with a paediatrician. If you have medically justified concerns, discuss them with your child’s doctor. They can recommend the safest modified option, one that minimises the risk to your child. Putting together your own schedule without medical advice is not recommended.

Does it hurt, and how can we comfort our child?

Vaccination causes brief pain at the moment of injection, which usually lasts 2-3 seconds. Most children calm down very quickly with the right injection technique and immediate comfort from a parent.

For babies under 1 year, the most effective approaches are:

• Breastfeeding just before, during or immediately after the vaccine
• A soothing dummy
• Gentle rocking and physical contact with the parent
• Talking softly or singing

For toddlers aged 1-3, these work well:

• Distraction with a book, toy or mobile device
• Blowing “bubbles” during the injection (deep breathing reduces pain)
• Positive words of support: “I’m so proud of you, you’re so brave!”
• Explaining beforehand what will happen, in simple words

For older children aged 4+, these help:

• An honest warning about what will happen: “You’ll feel a little pinch for 2 seconds”
• A choice: “Would you like it in your left arm or your right arm?”
• Visualisation: “Imagine you’re in your favourite place”
• A reward after the vaccination (a sticker, a small toy, a special activity)

What should we do after the vaccination?

After the vaccine is given, there are specific steps parents should take for their child’s safety and comfort.

Stay at the clinic for the first 30 minutes after vaccination. Severe allergic reactions (anaphylaxis), if they happen, appear within this time window in most cases. Medical staff have immediate access to emergency medicines and can respond within seconds.

For the first 24 hours after vaccination, watch for normal reactions. A slight temperature up to 38.5°C, redness or mild swelling at the injection site and irritability are a normal immune response. Paracetamol or ibuprofen (as recommended by the paediatrician) can help relieve discomfort if needed.

To reduce local discomfort, apply a cold compress (a nappy or cloth soaked in cold water) to the injection site for 10-15 minutes. Avoid massaging the area, as this can increase swelling and pain.

For the next 48 hours, keep to your child’s normal routine. Mild irritability, tiredness and reduced appetite are normal and need no special measures. Your child is not contagious after vaccination and can follow their usual routine, including nursery or school.

Don’t give fever-reducing medicine before vaccination as a precaution. According to medical observations, preventive use of paracetamol or ibuprofen before vaccination may slightly reduce the immune response. Only give fever-reducing medicine if it is actually needed once a temperature appears.

Watch for warning signs throughout the period after vaccination, and don’t hesitate to contact the paediatrician if you have any doubts (see the section “How do we recognise side effects that need a doctor straight away?” above).

Conclusion: why it matters to follow the recommended schedule

The immunisation schedule is the result of decades of global epidemiological research and clinical trials. According to the World Health Organization, child deaths from vaccine-preventable diseases have fallen significantly in recent decades thanks to mass immunisation worldwide.

Following the recommended schedule doesn’t only protect your child; it contributes to herd immunity, which protects the most vulnerable members of society: newborns too young to be vaccinated, immunocompromised people who cannot be vaccinated, and older people with weakened immunity.

If you have doubts, if your child has specific health conditions, or if you have questions about the immunisation schedule, always consult a paediatrician or paediatric immunologist. An informed decision based on medical facts is the best protection for your child’s health.

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*This article is for information only and does not replace professional medical advice, diagnosis or treatment. Always consult a qualified healthcare professional about questions related to your child’s health. In a medical emergency, call 112.

Sources:

• National Immunisation Schedule, Ministry of Health, Bulgaria
• World Health Organization (WHO), Immunization Guidelines
• Centers for Disease Control and Prevention (CDC), Vaccine Safety Information

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