Vaccines need to be administered at particular designated time in life to prevent the infection. For maximum effectiveness children are recommended to receive vaccinations as soon as their immune systems are sufficiently developed to respond to the components of the vaccines. Additional booster shots are required to teach the body fully to deal with the infection later in life. This requirement has led to the development of complex vaccination schedules.

How are vaccine schedules decided upon?

The schedules are decided upon by organizations. These schedules are decided upon based on the needs of the community, the local prevalence of the disease etc.

In the United States, the Advisory Committee on Immunization Practices recommends schedule additions for the Centers for Disease Control and Prevention. The ACIP recommends vaccinations of all children against:

• hepatitis A
• hepatitis B
• polio
• mumps
• measles
• rubella
• diphtheria
• pertussis
• tetanus
• HiB
• chickenpox
• Rotavirus
• Influenza
• meningococcal disease
• pneumonia

The schedules also recommend vaccines and boosters for older children, adolescents, adults, pregnant women, travellers and the elderly.

Combined vaccines

There may be up to 24 injections by the age of 2. Too many injections and complex schedules mean less compliance among general population. One way to deal with this is introduction of combined vaccines like MMR against measles, mumps and rubella.

Vaccines and prophylactic measures for travellers

Those who travel to countries where certain infections are prevalent are also at a risk of acquiring infections. CDC divides vaccines for travel into three categories: routine, recommended, and required.

Some routine vaccines are important for travel. These include the routine vaccines for children and adults (figures above). These vaccines are recommended to protect travellers from illnesses present in other parts of the world and to prevent the importation of infectious diseases across international borders.

Some specific travel related vaccines include yellow fever vaccination for travel to certain countries in sub-Saharan Africa and tropical South America. Meningococcal vaccination is required by the government of Saudi Arabia for annual travel during the Hajj etc.