Immunization

Why it is important - All key messages - Resources

Immunization protects children against some of the most dangerous diseases of childhood. All children, including those who are disabled, need to be vaccinated. A child is immunized by vaccines, which are injected or given by mouth. The vaccines work by building up the child's defences against diseases. Immunization only works if given before the disease strikes.

A child who is not immunized is very likely to get measles, whooping cough and many other diseases that can kill. Children who survive these diseases are weakened and may not grow well. They may be permanently disabled. They may die later from malnutrition and other illnesses.

All children need to be immunized with BCG (Bacille Calmette-Guérin) vaccine, which offers partial protection against some forms of tuberculosis and leprosy.

All children need to be immunized against diphtheria, tetanus and pertussis with DTP vaccine (also known as DPT vaccine). Diphtheria causes infection of the upper respiratory tract, which in severe cases may lead to breathing difficulties and death. Tetanus causes rigid muscles and painful muscle spasms and can be deadly. Pertussis, or whooping cough, affects the respiratory tract and can cause a cough that lasts four to eight weeks. The disease is very dangerous in infants.

All pregnant women and infants need to be immunized against tetanus.

• Immunizing a woman or adolescent with at least two doses of tetanus toxoid before or during pregnancy protects the newborn for the first few weeks of life and protects the mother.
• At 6 weeks old, a baby needs the first dose of tetanus toxoid (the tetanus component of the DTP (DPT) vaccine) to extend the protection received from the mother against tetanus.

All children need to be immunized against measles, which can be a major cause of malnutrition, poor mental development, and hearing and visual impairments. The signs that a child has measles are a fever and rash, together with a cough, a runny nose or red eyes. A child can die from measles.

All children need to be immunized against polio. The signs of polio are a floppy limb or the inability to move. For every 200 children infected, one will be disabled for life.

In countries where hepatitis B is a problem, up to 10 out of every 100 children will harbour the infection for life if they are not immunized with hepatitis B vaccine. Up to one quarter of children infected with hepatitis B may develop serious liver conditions such as cancer when they are older.

In many countries, pneumonia caused by pneumococcus bacteria or Haemophilus influenzae type B (Hib) bacteria is common and kills many young children. Either of these bacteria can also cause childhood meningitis and other serious infections. These bacteria are among the most dangerous for children, particularly those under 5 years old. Vaccination with Haemophilus influenzae type B vaccine (Hib vaccine) and pneumococcal (conjugate) vaccine (PCV) can prevent these deaths.

A pentavalent vaccine (five vaccines in one), combining the DTP (DPT), hepatitis B and Hib vaccines, is increasingly being used by national immunization programmes.

Diarrhoea caused by rotavirus is common and can be severe. It affects nearly every child under age 5. Severe rotavirus diarrhoea is more common in developing countries where health care can be more difficult to access, resulting in many deaths in children under 5 years old, especially children under 2. Vaccination against rotavirus prevents diarrhoea caused by this virus. However, diarrhoea due to other bacteria or viruses can still occur in children who receive the rotavirus vaccine.

In some countries, yellow fever puts the lives of many young children and adults at risk. Vaccination can prevent the disease.

Japanese encephalitis virus is spread by mosquitoes, mainly in rural areas of Asian countries. It causes a severe illness, killing up to one third of those affected. Many survivors have brain damage. A trained health worker should be consulted for advice and information on national guidelines regarding use of this vaccine.

Breastmilk and colostrum, the thick yellow milk produced during the first few days after a woman gives birth, provide protection against diarrhoea, pneumonia and other diseases. Colostrum is sometimes referred to as a newborn's 'first vaccine', helping to build the child's immunity to disease.

In many countries where vitamin A deficiency is common, high-dose vitamin A capsules (or syrup) are administered to each child aged 6 months to 5 years, every four to six months. Vitamin A is distributed during routine immunization (such as with measles vaccine at 9 months) as well as during special immunization campaigns. Vitamin A is also an important part of measles treatment.