Recommendations for UseThe standard schedule is three primary doses at 6, 10 and 14 weeks and two boosters at 15-18 months and 5 years. Early completion of primary immunization is desirable as there is no maternal antibody for protection against pertussis. The schedule for catch up vaccination is three doses at 0, 1 and 6 months. The 2nd childhood booster is not required if the last dose has been given beyond the age of 4 years. DTwP is not recommended in children aged 7 years and older due to increased risk of side effects. It is essential to immunize even those recovering from diphtheria, tetanus and pertussis as natural disease does not offer complete protection. |
Adverse ReactionsLocal (pain and redness) and systemic (fever) side-effects of the DTPw vaccine are almost entirely due to the pertussis component. Whole cell pertussis vaccine has been incriminated in the induction of a neurological reaction in very rare instances. However, there has been no conclusive proof for this and the vaccine should not be denied to children with seizure disorders or stable neurological conditions (e.g. Cerebral palsy, developmental delay). Some children develop persistent inconsolable cry of more than 3 hours duration, hyperpyrexia, (fever over 40.5 degrees C) or hypotonic - hypo responsive episode (collapse/shock like stage) within 48 hours of DTPw administration, seizures with or without fever within 72 hours of administration of DTPw. The decision to administer further doses of DTPw should be carefully evaluated and discussed with the parents. These events were regarded as absolute contraindications in the past. They are now considered mere precautions because these events generally do not recur with the next dose and they have not been proven to cause permanent sequelae. If a similar adverse reaction recurs with the subsequent dose only then pertussis vaccine is contraindicated for future administration. |
The morbidity and mortality due to diphtheria, tetanus and pertussis has reduced significantly in India since introduction of the whole cell vaccines in EPI. However coverage with 3 doses of the whole cell vaccine stands at 55% with booster coverage being even lower thus offering tremendous scope for improvement.
Popularly known as triple antigen, DTwP is composed of tetanus and diphtheria toxoids as well as killed whole cell pertussis bacilli adsorbed on insoluble aluminium salts which act as adjuvants. The content of diphtheria toxoid varies from 20 to 30 Lf and that of tetanus toxoid varies from 5 to 25 Lf per dose. The vaccines need to be stored at 2 to 8 C. These vaccines should never be frozen, and if frozen accidentally, should be discarded. The dose is 0.5 ml intramuscularly and the preferred site is the anterolateral aspect of the thigh. The immunogenicity (protective titer for diphtheria . 0.1 IU/ml and for tetanus . 0.01 IU/ml) and effectiveness against diphtheria/tetanus of three doses of the vaccine exceeds 95%. Disease may occur in vaccinated individuals but is milder.
The efficacy of the vaccine against pertussis is lower and as per data from international trials ranges from 70-90% (exception the US Connaught whole cell vaccine which is now withdrawn). Immunity against all three components wanes over the next 6-12 years and thus regular boosting is needed. Most adverse effects are due to the pertussis component. Minor adverse effects like pain, swelling and redness at the local site, fever, fussiness, anorexia and vomiting are reported in almost half the vaccinees after any of the 3 primary doses. Serious adverse effects have been reported with DTwP vaccines but are rare. The frequency of these side effects/ 1000 doses is 0.2-4.4 for fever more than 40.5C, 4-8.8 for persistent crying, 0.06-0.8 for hypotonic hyporesponsive episodes (HHE), 0.16-0.39 for seizures and 0.007 for encephalopathy.
The frequency of systemic reactions reduces and that of local reactions increases with increasing number of doses. Children with history of a reaction following vaccination are more likely to experience a reaction following future doses. Catastrophic side effects such as sudden infant death syndrome (SIDS), autism, chronic neurologic damage, infantile spasms, learning disorders and Reyefs syndrome were attributed to use of the whole cell vaccine in the past. It has now been proved beyond doubt that the whole cell pertussis vaccine is not causally associated with any of these adverse events.
Absolute contraindications to any pertussis vaccination (including DTwP vaccine) is history of anaphylaxis or development of encephalopathy within 7 days following previous DTwP vaccination. In case of anaphylaxis further immunization with any diphtheria/tetanus/pertussis vaccine is contraindicated as it is uncertain which component caused the event. For patients with history of encephalopathy following vaccination any pertussis vaccine is contraindicated and only diphtheria and tetanus vaccines may be used.
Events
such as persistent inconsolable crying of more than 3 hours
duration/hyperpyrexia (fever 40.5 degrees C)/HHE within 48 hours
of DTwP administration and seizures with or without fever
within 72 hours of administration of DTwP are considered as
precautions but not contraindications to future doses of DTwP
because these events generally do not recur with the next dose
and they have not been proven to cause permanent sequelae.
Progressive/evolving neurological illnesses, is a relative
contraindication to first dose of DTwP immunization.
However, DTwP can be safely given to children with stable
neurologic disorders.