Pentavalent vaccine: Doing more harm than good?

Immunisation with the new Pentavalent vaccine resulted in the recent death of two babies in Kerala. This combination vaccine was to replace the trivalent DPT (against diphtheria, whooping cough, tetanus vaccine) and additionally protects against Haemophilus influenzae type b and Hepatitis B. The post mortem certificate in both babies stated: “Based on the findings in the autopsy, preliminary reports of microbiological and histopathological findings, no definite opinion as to the cause of death can be furnished. Death due to natural disease, injury and aspiration pneumonia are ruled out. However, death as a result of post vaccination sequelae could not be ruled out.”1

Vaccines are administered to a large number of healthy children to protect against illness and death. The autopsy reports suggest that the vaccine was the most likely cause for the deaths but stopped short of saying the vaccine definitely caused the deaths.

All drugs have side effects, it has to be decided if the adverse effects are unacceptable. As children die from other reasons, unrelated to the vaccine there it is possible that coincidentally children may die of other disease on the day they were immunised. However for children noted as dying after pentavalent vaccine no ‘alternate and sufficient cause’ was found to explain the death in spite of diligent investigations. Even if no alternate cause of death is established the possibility of ‘Sudden Infant Deaths Syndrome’ (SIDS) exists where deaths happen without explanation.

Deaths in several countries where the vaccine is used

The two deaths whose autopsy reports are discussed above are not the only deaths associated with this vaccine. This vaccine is used mostly in developing countries. There were eight deaths in Bhutan.2 There were 25 instances of serious adverse events in Sri Lanka including five deaths.3 There were three deaths in Pakistan.4 There were 10 children who suffered serious adverse events of whom seven died in Vietnam.5 There were at least 15 deaths in Kerala6 and two in Tamil Nadu7 and one in Haryana8 making the total 18 deaths in India. These deaths, in different countries using vaccine from varied manufacturers, rules out defects in some specific batch of the vaccine, and also indicate that they are unlikely to be because of incorrect administration of the vaccine. The WHO considers two deaths due to vaccination as a cluster9 that mandates rapid evaluation of the risk to public safety.10 That there are 41 deaths are a matter of serious concern. Should the programme be now suspended?

Infant mortality rate and coincidental death on day of immunisation

Information obtained under the right to information suggests that in the first six months, when the vaccine was administered to 40,000 children in Kerala, five children died. If this is extrapolated and the 25 million babies in India born each year are vaccinated we can expect 3125 deaths.

These deaths from the vaccine would seem to outweigh any benefit that immunisation can yield. In Kerala 14 babies die before their first birthday per 1000 live births. This is called the infant mortality rate (IMR). Half of these deaths occur in the first month of life. The other seven deaths per 1000 occur in the remaining 11 months. Pentavalent vaccine is administered after six weeks of age, and so it is administered to babies who have survived the first month of life. Four out of five deaths occurred with the first dose of the vaccine and on the day or the next day of vaccination. The death of babies in the first day after vaccination works out to be four times higher than the expected number. The vaccine meant to save lives seems to be increasing mortality rather than reducing it.

Deaths from SIDS

Pentavalent vaccine is given to healthy babies. Mothers in Kerala don’t ordinarily bring very sick babies for immunisation. Each baby is examined by healthcare personnel before vaccination. So sick babies are unlikely to receive vaccination. Babies who die are usually severely ill. The deaths in these vaccinated babies are deaths in apparently healthy babies who no one anticipates will die in the next few hours. Another possibility is the rare SIDS, the death of an apparently healthy baby without explanation. SIDS may be the explanation for a very small number of deaths. Here the ‘unexplained deaths’ following immunisation, are four times the number that usually die after the first month of life. SIDS is very unlikely to be the explanation for these deaths following Pentavalent vaccination. Furthermore, the SIDS rate in the third month of life is higher than that in the second month, and if these deaths were merely coincidental with the Pentavalent vaccine there should be more deaths after the second dose rather than the first. However, four of the five deaths in the first six months in Kerala, were after the first dose. This also argues against all these deaths being SIDS deaths.

Lives lost to adverse events against lives saved by vaccination

One method to decide on continuing the programme would be to see if more harm is done than the benefits (reducing disease deaths in the community) by vaccination.

Pentavalent vaccine provides protection against Hib disease. Evidence from the World Health Organization studies in India suggests that seven children in 100,000 get Hib meningitis of which 10 per cent die. If the 25 million babies born each year are immunised it will prevent 8750 cases of Hib meningitis and 875 deaths over the next five years. Vaccination also protects children against pneumonia: more children get Hib pneumonia but few die of it. If we double the estimated deaths about 1750 children in the country die each year from HIb disease and these can be saved by immunisation. We cannot estimate the lives saved by Hepatitis B immunisation as they do not happen in childhood. The deaths from the vaccine (3125) seem to outweigh the benefits (1750 lives saved).

The parallels with Rotavirus vaccine withdrawal

In 1999 the newly introduced Rotavirus vaccine in the West was suspected of increasing ‘intussusceptions’ (a surgical condition of the small intestine). Ordinarily one in 10,000 children would get intussusception. This went upto 2/10,000 in the two weeks after the first dose of Rotavirus vaccine was administered. When 15 extra cases of intussusceptions were noticed (and when not even one baby had died) the vaccine was withdrawn.11 Product liability rules are so stringent in the West that the manufacturers voluntarily removed the vaccines before they were asked to.

Noel Narayanan Commission and underestimation of adverse events

Before starting the programme in Kerala the Government set up theNoel Narayanan Committee12. It recommended the Government collect data on each child immunised with the vaccine, for 48 hours after immunisation. A government affidavit to the Delhi High Court suggests this was not done in a systematic way but reporting of adverse events was left to voluntary ASHA workers13. They are given incentives depending on the number of children receiving Pentavalent vaccine in their area. This could be a disincentive for reporting adverse events as, such reports could reduce vaccine uptake and her earnings.

There are the Government Standard Operating Procedure (SOP) for adverse events following immunisation (AEFI)14. The numbers reported suggest severe under-reporting: while over 100 serious adverse reactions of various types would be expected with the standard DPT (triple antigen) vaccine in six months, only two were reported with Pentavalent vaccine that incorporates the DPT. In addition it appears there was an attempt to blame the parents of the first child who died following immunisation in Kerala. The press reported that the baby did not die of vaccine reaction but was smothered15 to death and later a spokesperson for the Health Department claimed the mother’s breast-milk feeding killed the child.16 It took the post-mortem report to clear the parents of these accusations. Given these circumstances it is clear that adverse events are likely to be under-reported and we can anticipate that the 15 deaths reported from Kerala, is an underestimation.

Post-marketing surveillance and concluding remarks

Notwithstanding any deficiency in the Government reporting system, the vaccine manufacturer is obliged to provide the Drug Controller with a listing of all side effects in the first few years of marketing a newly licensed drug. The Drug Controller is the regulatory authority which has to ensure such reporting is made available.

Most of the information presented here pertains to the first six months of the programme in Kerala for which information was made available under the RTI. The public must insist that data for the 14 months the vaccine has been in use in Kerala and Tamil Nadu is carefully evaluated in a transparent manner before decisions are made for the health and safety of our children.

(Disclosure: In December 2009 a former Union Health Secretary Professor KB Saxena and eight others filed a public interest petition in the Delhi High Court to ask the Government of India to formulate an evidence-based rational vaccine policy for introducing new vaccines and to ensure that the basic EPI vaccines are provided to every child without discrimination or constraints of funds. The author is one of the petitioners. Since August 2010, he is a member of the National Advisory Group on Immunization. (NTAGI)).

The opinions expressed in this article are those of the author.

References:

Pentavalent vaccine: Doing more harm than good?

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