Right Parenting - DPT and Hib Vaccines

DPT is a combined vaccine against three deadly diseases – Diphtheria, Pertussis and Tetanus. More commonly it is called the ‘Triple’ vaccine.

What is Hib vaccine?

Hib vaccine offers protection against infections of bacteria known as H.influenzae type b. These bacteria can cause severe and at times life-threatening infections of ear, nose, throat, sinuses and brain. Children below 6 years are most likely targets of these infections.

What is Diphtheria?

Diphtheria is a contagious bacterial illness caused by the toxin of bacteria called Corynebacterium diphtheriae (C.diphtheriae). It usually starts as a severe sore throat where a grayish or blackish membrane is covering the throat and causes difficulty in swallowing and breathing. In advanced cases, even heart, kidneys and nervous system get affected. Most of the cases occur under the age of five years and almost 50% of the untreated patients can die.

What is Pertussis?

Pertussis is another contagious bacterial disease caused by Bordetella pertussis (B.pertussis). It starts as a common cold-like illness but proceeds to a severe kind of cough called ‘Whooping cough’, where long spells of coughing are interspersed by a gasping ‘whooping’ sound. The patient often goes blue in face while coughing and vomits afterwards. Most of the cases are seen in infancy and although it is not deadly, the illness has a long course of almost 2-3 months.

What is Tetanus?

Tetanus is a life-threatening disease caused by the toxin of the bacteria called Clostridium tetani. This toxin known as tetanospasmin, affects the nerve function and causes muscle spasms. Contaminated wounds are the usual entry portals for these soil-residing bacteria. The illness often starts as the spasm of the jaw muscles causing ‘Lock-jaw’ and then becomes more generalized. It has a high mortality rate – especially in the newborn babies, where it might kill more than 95% of affected babies.

How are these diseases treated?

Proper antibiotics, anti-toxins (in diphtheria and tetanus) and good supportive care are the mainstays of treatment. But still prevention through vaccination remains the best and most effective treatment.

What is the efficacy of the DPT and Hib vaccines?

DPT vaccine offers about 85% protection against pertussis and almost 100% protection against diphtheria and tetanus. Hib vaccine offers almost 90-95 % protection.

What is the recommended DPT and Hib schedule?

In developed countries (like UAE) where health standards are good, the primary vaccination of both, DPT and Hib should start at the age of two months. DPT + Hib injections at 2, 4 and 6 months complete the primary series. A booster should be given at 18 months.

In developing countries like India, Pakistan and Bangladesh, the primary series should start earlier – at the age of 1 and 1/2 months and the interval between each dose should be less i.e. 4-6 weeks. This is because of the higher risk of these illnesses in these countries.

Sometimes, in developing countries Hib vaccine is often (and unfortunately) avoided as an ‘optional’ vaccine. If such a baby, who has missed out Hib vaccine, is less than 6 months in age, then it requires all three Hib vaccine doses, spaced one month apart, followed by an 18 month- booster. If such a baby is in 6 – 12 months age-group, then it requires 2 doses of vaccine spaced one month apart, with the 18 month booster dose and if it is more than 1 year in age, just a single dose of Hib suffices.

What are the side-effects of these vaccines?

Mild fever is possible. As this vaccine is given as a deep intra-muscular injection in the thigh, limping, pain and redness at and around the injection site are the common side-effects. Usually they subside within 2-3 days. Most of these side-effects are avoidable if analgesic/antipyretic medicine like Paracetamol is started soon after vaccination and then continued for a day or two.

Sometimes a nodule like swelling is felt under the skin at the injection site and it can even last for a few months. It is harmless and self-limited.

What are the associated complications?

Skin infection like cellulitis and abscess can happen occasionally at injection site and should be suspected if swelling, redness and pain persist after three days of injection.

Severe screaming or high-pitched crying episodes lasting for more than 4 hours, convulsions, shock, encephalopathy (Brain affection) and very high grade fever (more than 105*F) are other and more serious complications of DPT vaccine. Fortunately these severe complications are pretty rare.

When is DPT contra-indicated?

Progressive neurologic disease, uncontrolled convulsions or severe complications observed with previous DPT dose are the situations where DPT is contra-indicated.

What are DT and Td?

Since most of the complications associated with DPT are due to pertussis component, DT – vaccine is often used successfully to prevent diphtheria and tetanus in cases where DPT use is not possible. After the age of six years, the risk of severe pertussis is negligible and the likelihood of associated vaccine-related complications is much higher, so DT is preferred booster injection.

After 10 years, even diphtheria component of vaccine can give rise to severe reactions and then Td – a vaccine with full amount of tetanus vaccine but reduced amount of diphtheria vaccine is used.

What is DaPT?

It was found that the whole cellular version of Pertussis vaccine, which is routinely used in DPT vaccine contains a troublesome antigen – LPF (Lymphocyte promoting factor), which causes most of the complications. So DaPT – a vaccine containing a purified ‘acellular’ version of pertussis was developed. Because of its high cost and relative rarity of routine DPT reactions, this vaccine has still not reached the mainstream.

What are tetra-, penta- and hexa- valent vaccines?

To reduce the number of injections during the vaccination schedule and to improve convenience and compliance, scientists have come up with combinations of vaccines. In the tetravalent vaccine – diphtheria, pertussis, tetanus and H.influenzae –b vaccines are combined. In Pentavalent vaccine, in addition to these even Hepatitis B vaccine is added. In Hexavalent vaccine, in addition to previous 5 vaccines, Inactivated (or Injectable) Polio vaccine is also added.

In the end, I would offer one important advice to every reader, don’t dwell on the negatives of vaccination for too long. They have been mentioned just to alert you- not to scare you away from the vaccines! The risks associated with vaccines pale into insignificance when you consider the tremendous benefit offered by them to mankind in its conquest of disease and death!

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