Special Assistant to the Prime Minister on Health Dr Zafar Mirza and the prime minister's former focal person on polio on Friday denounced a report published by British daily The Guardian, in which the publication had accused Pakistani officials of "covering up" a polio outbreak.

The report in question, published in The Guardian on November 7, accused Pakistani officials of "covering up an outbreak of the most dangerous strain of polio and planning a covert vaccination programme to contain the disease".

According to The Guardian, an outbreak of the P2 strain of the virus was allegedly kept hidden from the government as well as international health bodies and donors "on the orders of Babar bin Atta", who was the prime minister's focal person for polio eradication until he resigned last month.

"[In order to] hide their negligence and their poor performance, Babar Bin Atta decided not disclose the cases to anyone," The Guardian quoted an unnamed source as saying. The report further said that the virus was believed to have reemerged because the vaccine to prevent its spread was misused.

"Somewhere, somebody has inaccurately used this vaccine and because of this negligence […] this virus was brought back into the environment and our children are again getting infected with P2," the report quoted the source as saying.

Pakistani officials rushed to correct the record today. "[There has been] absolutely no cover up," Dr Mirza responded to the story in a tweet earlier today.

Talking to Dawn earlier, Dr Mirza had said that seven new cases of the vaccine-derived poliovirus Type 2 had been detected in the country.

"This is not a wild poliovirus outbreak. It is an outbreak of the Sabin-Like Type 2 Derived (SLT2D) [strain]," he said. "Similar outbreaks [of SLT2D] have been recently reported in Philippines, China, Indonesia, Nigeria, Democratic Republic of Congo and several other countries in Africa which have [otherwise] completely eradicated the poliovirus."

"SLT2D virus outbreak in Pakistan is vigilantly being monitored and appropriately responded," he assured in a tweet.

There are three serotypes of the wild poliovirus, Type 1, Type 2, and Type 3.

Pakistan has been immunising against Type 1 and Type 3 viruses through oral polio vaccines (OPVs). It had stopped administering vaccines for Type 2 virus in 2014 after it was believed to have been eradicated. The virus could not be found even in environmental samples since 2016, officials said.

The Type 2 vaccine was discontinued as it contains specimens of the virus that can spread disease if not used appropriately.

"However, suddenly cases have been reported from different areas, which means there was some vial [of Type 2 vaccine] left in some laboratory or somewhere else and started spreading due to human error," Dr Mirza told Dawn.

"Just after getting the cases — which cannot be included in the number of wild polio virus [cases, as The Guardian has alleged] — we sent samples to the Centres for Disease Control and Prevention (CDC), Atlanta, and after getting confirmation that children were paralysed due to Type 2 polio virus, we have started polio campaigns," Dr Mirza said.

Babar rejects allegations

Separately, Babar rejected the allegations against him, calling them "absolutely baseless". He said that he was writing to the British daily to set the record straight.

"The Guardian report is absolutely baseless. I am writing to them to correct the record and issue an apology, failing which I shall pursue my legal options. I shall be sending relevant documents to @guardian to prove their 'He Said - She Said' report wrong. Enough of this slander," he said in a tweet.

In another tweet, Babar pointed out that though the reporter, Hannah Ellis-Petersen, was based in New Delhi according to her Twitter profile, she had not contacted him for a comment on the matter.

He also accused her of "misreporting [the incidence of] circulating vaccine-derived polio viruses (VDPV) as [the] P2 virus".

The SLT2D strain, which has been found circulating in Pakistan, is a VDPV.

"[The reporter] did not mention same VDPV contamination in India 2018; hid the fact that VDPV does not add to [a country's official] polio case tally; did not mention same VDPV strain [is also] found in [otherwise] polio free countries," he pointed out.

Babar also rubbished the charge that he could have covered up polio cases, pointing out that the monitoring of cases is done by external agencies that he has no control over.

"[...] Surveillance is a World Health Organisation subject. What authority does an honorary "Focal Person" have to instruct a United Nations agency?" he asked in a tweet. "[The UK] Department for International Development (DFID) pays to the Global Polio Eradication Initiative (GPEI), not to Pakistan directly [...] They should have contacted me for a version, I would've educated them."

Working to enhance immunisation coverage: PPEP

In an official statement, the Pakistan Polio Eradication Programme said that the seven cases of SLT2D poliovirus which had been detected were present "mainly in the northern parts of the country".

"The only way to reduce the risks of further transmission is to address gaps in immunisation coverage. The programme is working on a comprehensive outbreak response that includes rounds of vaccination in the area to protect every child under the age of five years.

"The programme has also enhanced its acute flaccid paralysis (AFP) surveillance by active search for additional cases, increasing testing of contacts of cases and strengthening environmental surveillance."

During the current year, 80 polio cases have so far been reported in Pakistan.