Immunisation

An immunisation, often called a vaccine, is given to help the body develop a protective defence (called immunity) against some serious diseases, some of which are of particular relevance in childhood. These vaccines can be given orally or by injection and are a common and important part of any child's early life.

 

Immunisations are given on a schedule that usually begins at birth. For most vaccines, one dose is not enough. Your child has to have all of the doses of vaccine to help the body develop immunity as it matures. Recommendations change from time to time, and the schedules vary from country to country. Ask your doctor if you have any questions.

 

The diseases for which childhood vaccines are given include:

 

  • diphtheria
  • tetanus
  • pertussis (whooping cough)
  • meningitis
  • poliomyelitis (polio)
  • measles
  • mumps
  • rubella (German measles)
  • hepatitis B
  • varicella (chickenpox)
  • tuberculosis (TB)

Are vaccines safe?

Generally speaking, vaccines are well tolerated and safe. There is much more danger to your child from the diseases than from the vaccines. In most children, the side effects of immunisations are mild and go away in a few days.

They do in most cases involve an injection, which is not always pleasant for both child and parent, however, modern combination vaccines mean that in many cases one injection may be all that is needed per visit which is an important advance.

How do vaccines work?

Broadly speaking, there are two different types of vaccine which work in different ways:

1. Live/Active vaccines - these cause a mild, non-clinically significant form of illness to induce the body's defence system to produce antibodies against the serious form of the disease.

2. Killed/Inactive vaccines - these expose the body to "killed" parts of the virus/bacteria that cause these conditions to try to induce antibody production to stop potential infection. Both Live and Killed vaccines are present in the current vaccination schedules. They are both effective in their own ways to prevent illness and are equally well-tolerated.

There are some people who should not receive live vaccines. This should be discussed with your doctor prior to vaccination.

What vaccines are commonly used?

 1. DTPa Vaccine

This is the recently introduced vaccine which offers protection against diphtheria, tetanus and pertussis, which are all serious and life threatening infections. The vaccine has a much lower incidence of side effects than the previous DTP vaccine ("triple antigen") and is suitable to use from birth up to 8 years. It is currently given in combination form with Hib / IPV vaccines.

 

2. Polio Vaccine

This vaccine helps prevent polio, a disease that can cause paralysis and death. The vaccine is available in two forms - Oral Polio vaccine (OPV) and Injectable Polio Vaccine (IPV). The OPV has been widely used around the world and is still the most commonly used vaccine today. In the USA, there has been a recent trend to use IPV due to possible concerns with OPV use. It is likely that in the future the IPV will be the most commonly used vaccine as it has just been released as a combination vaccine with the DTPa thus lessening the need for an oral dose during the vaccination visit.

 

3. Hib Vaccine

Haemophilus influenzae type b (Hib) vaccine protects against a serious illness that can lead to meningitis, pneumonia and a severe throat infection that can cause choking. The vaccine is safe, extremely effective, and has a very low incidence of reaction. It is commonly given as a mixed vaccine with DTPa and IPV, and is safely recommended for use up to age 5 years.

 

4. MMR Vaccine

Measles, mumps and rubella (MMR) vaccine protects against these 3 common childhood illnesses. Measles is a serious and extremely contagious illness which can cause brain swelling and even death. Mumps can lead to meningitis, and can also cause orchitis (inflammation of the testicles), which can result in male sterility. Exposure to rubella during pregnancy can put the developing baby at risk from blindness, mental retardation and deformity. The MMR vaccine is a safe and effective vaccine. It may lead to a rash or fever and may cause some aching or swelling of the joints one to three weeks after vaccination. This is more likely to occur in adults than in children.

 

5. HBV Vaccine

Hepatitis B vaccine (HBV) protects against infection with Hepatitis B, a virus that can cause liver disease, liver cancer and death. The vaccine is very effective and safe to use from birth. It is available as a single vaccine, or can be given in combination with the Hepatitis A vaccine to increase the cover against this common illness.

 

6. Varicella Vaccine

Varicella vaccine helps protect against chickenpox, a common illness that causes fever, itching and a blister-like rash. Skin infections are common complications. Rare complications include pneumonia, swelling of the brain, and death, especially in adults and children who have defective immune systems. This vaccine is recommended as a single dose vaccine at age 1, and is safe to administer with other vaccines. If used in adults, two doses of vaccine are needed.

 

7. BCG Vaccine

This is the commonly used vaccine to prevent Tuberculosis (TB), which is the most common cause of death from infectious disease worldwide. This is of particular relevance in SE Asia where the incidence of the illness is 40 times greater than the Western world. TB is predominately a chest infection, generally of slow onset and low infectivity, which can have serious consequences as it can spread to other parts of the body causing serious illness and even death. The very young or immune depressed are at the most risk.

 

The bacteria that causes TB is becoming more resistant to antibiotic therapy and hence there is more of a trend to recommending vaccination. Many countries have differing attitudes to BCG Vaccination, however there is agreement that young children living in a high risk area for any length of time should be offered the vaccine. This is best given at birth by a single injection. If given to children over 6 months of age it will need to be preceded by a mantoux or skin test.