The UK childhood immunisation schedule explained

Why the schedule is timed the way it is

Vaccines work by safely teaching the immune system to recognise a germ, so that if the child meets the real infection later, their body can fight it off quickly. The schedule is timed so that protection arrives before a child is most likely to be exposed and at greatest risk. That is why some vaccines start at just eight weeks of age, when babies are especially vulnerable to certain infections and have lost some of the protection passed on from their mother. Several vaccines are given as a course of more than one dose, spaced apart, because the immune system responds more strongly and for longer when it is reminded. Booster doses later top up protection that naturally fades. This careful timing, based on decades of research, gives the best and longest-lasting defence.

Vaccines in the first year

In the first year of life, babies are offered several vaccinations, usually starting at eight weeks and continuing at twelve and sixteen weeks, with more around one year of age. A single combined injection protects against several serious infections at once, including diphtheria, tetanus, whooping cough, polio and others, which means fewer separate jabs. Babies are also protected against infections that can cause meningitis and blood poisoning, and against a common cause of severe diarrhoea and vomiting given as drops by mouth. Around their first birthday, children receive further doses and boosters to strengthen and broaden their protection. Giving several vaccines together is safe and does not overload a baby's immune system, which copes with countless germs every day. The result is strong early protection during the months when babies are most at risk of severe illness.

The pre-school years

As children grow, they are offered further vaccines to reinforce earlier protection and guard against new risks. Around the age of one, and again before starting school at about three years, children receive the MMR vaccine, which protects against measles, mumps and rubella. These are given as two doses because a second dose greatly improves protection, especially against measles, which can be very serious. A pre-school booster also tops up protection against diphtheria, tetanus, whooping cough and polio before children mix in larger groups. Each winter, young children are offered a nasal spray flu vaccine, given as a quick squirt up the nose rather than an injection, to protect them during the flu season. Keeping up with these pre-school vaccines ensures children are well protected as they start nursery and school, where infections spread more easily.

School-age and teenage vaccines

Vaccination continues into the school years. Children are offered the flu nasal spray each year through primary school. A vaccine that protects against a virus called HPV, which can cause several cancers later in life including cervical cancer, is offered to both girls and boys in early secondary school. In the teenage years, young people are offered a booster protecting against tetanus, diphtheria and polio, and a vaccine covering several strains of the bacteria that cause meningitis and blood poisoning, which is especially important before the closer living of college or university. These later vaccines protect against illnesses that become more relevant as children grow up and become more independent. Many school vaccines are given during the school day with parental consent, making them convenient, though they can also be arranged through a GP if missed.

Safety, side effects and catching up

NHS vaccines are thoroughly tested before use and monitored continuously afterwards, and serious reactions are very rare. Most side effects are mild and short-lived, such as a sore arm, a small lump at the injection site, being a bit irritable, or a mild raised temperature for a day or two. These are signs the immune system is responding and usually settle quickly. Vaccinating enough children also protects those who cannot be vaccinated, such as very young babies or children with certain illnesses, by reducing the spread of infection in the community — an effect known as herd protection. If a child misses a vaccine, it is almost always possible to catch up; a GP or practice nurse can check your child's records and arrange any missed doses. If you have questions or concerns, your health visitor, practice nurse or GP can talk them through with you.