28 October, 2009 - Two months after being introduced nationwide, the health ministry has alerted all hospitals to immediately stop vaccinating infants with the pentavalent vaccine, because it may have side effects.

The circular, which was sent on October 23, states, “… the use of pentavalent vaccine should be stopped immediately due to some side effects. All adverse events following on immunisation (AEFI) must be strengthened, reported and investigated.”

The ministry’s media spokesperson, Kado Zangpo, said that, while the investigation is on, health centres will continue to immunise infants the way it was done before the introduction of pentavalent vaccine. “We have asked the world health organisation to come and do the investigations,” said the spokesperson.

Pentavalent vaccine was introduced to protect infants against pneumonia, one of the leading causes of death in children under 15 years in Bhutan, and meningitis. It’s a combination of vaccines against diphtheria, whooping cough (pertussis), tetanus, hepatitis-B and the haemophilus influenza type B (Hib) germ.

Details regarding the side effects are, however, sketchy. The ministry will be briefing the press with more details today at 2:00 pm, said health officials.

Doctors say that no vaccine is free of side effects and that they change when vaccines are combined. Vaccines generally cause pain in the place of injection, swelling, redness, irritability and fever. Some are serious like allergies and can be fatal, say doctors.

Side effects of pentavalent vaccine Non-fatal AEFIs, described as hypotonic-hypo responsive episode (HHE), are a recognised adverse reaction to such vaccines. HHE is characterised by sudden onset of reduced muscle tone, hypo responsiveness and pallor or cyanosis, a condition in which the skin becomes bluish because of a lack of oxygen in the blood. Studies have shown that HHE lasts for a short period and has no long-term consequences for the child. In Sri Lanka, a “hyper-response” was observed in a number of children, who were given the vaccination.

Bhutan received a total of 30,200 pentavalent vaccines from the global alliance for vaccine initiative (GAVI), which can vaccinate 1,100 babies. In a year, about 13,600 newborns are immunised across the country.

All unused vaccines will be collected by the ministry’s cold van, according to the circular. But, while some district hospitals have collected their unused stock of pentavalent vaccines, in some, the collection is still on.

Pemagatshel, for example, which received 300 doses, has a leftover of 180 ready to be returned. But, Trashigang, one of the largest districts, is still collecting vaccines from health units in the far-flung areas.

Last year in April, Sri Lanka withdrew the pentavalent vaccine as a precautionary measure, following five reports of fatal AEFIs and 20 reports of non-fatal AEFIs. However, the report of the WHO expert panel that reviewed the data found no evidence of a relationship between the pentavalent vaccine and any of the five deaths reported. The vaccine remains on the list of WHO prequalified vaccines and Sri Lanka resumed the vaccination from this year.

This is the first time, a vaccine has been stopped in Bhutan since the extended program for immunisation (EPI) was launched in 1979.