Vaccines are made of dead/live attenuated viral or bacterial products called “antigens.” They stimulate the defence mechanisms of the body and lead to the formation of certain protective proteins called “antibodies” in the body. For example when your child receives Polio drops (containing attenuated live Polio viral antigen); the body produces antibodies against it. Later on in life, supposing your child comes into contact with the Polio virus, because of the wise step taken by you in getting your child immunised, the child has the capacity to resist this infection because of the protective antibodies formed in his body earlier due to the vaccination. Hence the child doesn’t suffer from Polio. This holds true for all diseases against which vaccines are available. What are the different types of vaccines?
1. BCG: It is a vaccine given to protect against tuberculosis (T.B.). Usually given at birth intra-dermally in the upper arm, it causes a swelling at the injection site that ulcerates and ultimately heals to leave a scar. The whole process from the time of injection to the formation of the scar may take 8-12 weeks. I often encounter anxious parents with the complaint that the injection has ‘reacted’ and there is a swelling at the local site. As mentioned above, this is normal. A child may get T.B. in spite of being vaccinated as amongst all vaccines, BCG is the least efficacious.
It has got a protection rate of about 50% (as compared to other vaccines whose efficacy is 90-95%). BCG does protect against the severity of the disease. So until a better vaccine is available, BCG is recommended, particularly in a country like India where T.B. is rampant. Another rare side effect of the vaccine is that few children may develop a swelling in the armpit, which is nothing else but lymph glands. It is benign and over a period of time subsides. However if it doesn’t subside, consult your paediatrician who will prescribe medicines for it. A 2nd dose (called the “booster dose”) is generally not recommended.
2. Polio: It is given at birth along with BCG (2 drops orally). Booster doses are given along with DTP (diphtheria, pertussis and tetanus), at 1.5, 2.5, 3.5, 18 months and finally at the age of 5 years. It protects against a disease called Polio, which can have devastating effects like paralysis of one or more limbs. Up to Vi hour after giving Polio, do not administer warm liquids to the child. However, breast milk can be given immediately.
3. DTP vaccine: It is a triple vaccine protecting against three diseases namely diphtheria, pertussis and tetanus. It is given intramuscularly in the anterolateral aspect of the thigh. The schedule is similar to that of Polio except that it is not given at birth. It can cause local pain at the injection site and also fever and irritability in the child. The treatment is to do cold compresses at the local site and the administration of paracetamol drops/syrup (10-15 mg/kg/dose) which can be repeated every 6 hours. Sometimes a few days after giving the DTP injection, the parents may feel a small, firm nodule at the site of injection. It doesn’t require any treatment and will spontaneously regress with time.
4. Measles vaccine: It is a live attenuated viral vaccine given at the age of 9 months in India (in western countries it is given at the age of 15 months as a triple vaccine, MMR). In India it is given earlier because of the common prevalence of this disease. The administration of this vaccine can also cause fever and a mild rash (5-7 days post vaccination). The treatment is same as for DPT injection.
These 4 vaccines are recommended by the National Health Policy of India and also form a part of the WHO schedule of Immunisation for the developing countries to protect against the 6 major killer diseases considered to be common and associated with a lot of deaths. These vaccines are supplied free of cost at all government dispensaries.