A spike in the number of polio cases in Pakistan — the last refuge of the virus in the world along with neighbouring Afghanistan — is being attributed by health experts to disruption in vaccination services caused by lockdowns and restrictions against spread of the COVID-19 pandemic.
"The increase in polio cases could result in the global export of infections and healthcare authorities must intensify efforts to track and vaccinate unvaccinated children, says Misbahud Din, researcher in molecular biology and immunology at Quaid-i-Azam University, Islamabad and lead author of a study, published October online in Public Health, on polio vaccination disruptions due to COVID-19 in Pakistan.
Din tells SciDev.Net that "80 cases of wild polio virus (WPV) and 64 cases of circulating vaccine-derived poliovirus (cVDPV) have been reported in 2020".
According to the study, around 40 million children missed polio vaccination after Pakistan, on 26 March, suspended a mass vaccination programme being carried out under the Global Polio Eradication Initiative (GPEI).
With support from UNICEF, WHO and GPEI partners, the Pakistan government resumed polio immunisation late July and conducted the second of two sub-national campaigns in August as COVID-19 cases started declining in the country.
But enforcement of social distancing, vaccine supply disruptions and elevated shipment costs during the four-month break had caused a momentum loss in a concerted drive to make the country polio-free.
Two years ago, with only 12 reported cases, Pakistan had come close to becoming polio-free. But the number of cases rose to 147 in 2019. According to Din, the sharp reversal was due to "illiteracy, vaccine refusal by parents, poverty, conspiracy theories and rejection of vaccination by some local religious scholars".
Concerted efforts early 2020 led to expectations that the year would see a halt in polio transmission by 2021. But the country was then hit by COVID-19, resulting in massive diversion of public health resources to tackle the new threat.
The suspension of immunisation activities and disruptions in other health-related interventions due to COVID-19 pandemic from March to mid-July has increased the number of unimmunised children, including close to 700,000 new-borns per month, leading to widening immunity gaps, says a UNICEF report.
"It could be concluded that diverting public health funds to fight against other outbreaks disrupted polio eradication plans, which could lead to the spread the of poliovirus in areas of low immunization coverage and immunity," the new study noted.
Din adds that it is "challenging for countries like Pakistan with limited health care facilities to deal with the current pandemic along with other outbreaks liked dengue, malaria and typhoid because COVID-19 overburdened the health care system.
Staff already trained to handle polio vaccinations were directed to fight against the COVID-19 pandemic".
Palitha Mahipala, WHO representative in Pakistan, commented on World Polio Day on 24 October that following the certification of the African region as free of wild polio virus in August, his organisation is "working hard to ensure that Pakistan can be the next country on the journey to a polio-free world".
The polio programme with its partners has now been able to ramp up activities with a revitalised resolve to end polio in Pakistan as recently done by Africa."
Palitha Mahipala, Representative, World Health Organization
Din, M., et al. (2020) Delays in polio vaccination programs due to COVID-19 in Pakistan: a major threat to Pakistan's long war against polio virus. Public Health. doi.org/10.1016/j.puhe.2020.09.004.