India’s polio scare made headlines in October. However, it has since faded from the forefront of media stories.
In mid-October it was found that live type-2 polio strains were circulation in samples of vaccines. This sparked concerns that India was facing a polio resurgence. These fears may have been overblown as reporting on the matter has fallen silent.
The most recent stories reported that the Indian government were sending an investigation team to the Indonesian pharmaceutical company PT Bio Farma — the original manufacturers of the vaccine — to establish what occurred.
The vaccines were purchased from PT Bio Farma by Indian company Biomed Pvt. Ltd. The director of Biomed Pvt. Ltd. was arrested following the incident, though later freed on bail.
The government is currently considering filing a special leave petition in the Supreme Court against the Ghaziabad district court’s decision to grant bail. The implication of this is that the government believes the director is responsible for, at the very least, gross negligence.
Progress against polio has been a success story globally. Only a few cases remain in just two countries: Pakistan and Afghanistan. Nonetheless, India’s recent scare highlights the importance of vigilance for countries where polio has been eradicated, to ensure that the disease remains a thing of the past. What is especially concerning in this incident is the strain of polio involved.
Type-2 polio has not been seen in India since 1999. As per World Health Organization (WHO) guidelines,the type-2 strain should not be present in oral vaccines in order to reduce the potential for vaccine-derived polio to occur. Due to this, immunisation rates against type-2 polio may be far lower than when the vaccine was circulating. The implication of this is that, if the strain were to find its way back into the population, it could spread rapidly between individuals and communities before an effective new vaccination campaign against it could be organised.
Though polio is eradicated in India, it is one of the most vulnerable countries for a potential new outbreak. This is due to it sharing a border with Pakistan. It is not improbable that an individual harbouring the virus could cross the border. As such, India must maintain a state of vigilance.
Incidents such as the recent scare have occurred in the past in other countries. In 2014, the pharmaceutical company GlaxoSmithKline accidentally dumped 45 litres of fluid containing the live polio virus into the Laan river in Belgium. The virus was not detected further downstream than the water processing plant. Crisis was averted, but the incident served to highlight potential risks in the future.
Situations such as the contamination in India and the accident in Belgium spotlight the very real risk of human error precipitating outbreaks of polio. Such drama is not necessary for the disease to return, however. If vaccination rates drop following eradication, even a single undetected case from a remote rural location could result in a future outbreak – and, if it were to go undetected, resurgence on a much wider scale.