Health authorities in Mozambique today declared an outbreak of wild poliovirus type 1 after confirming that a child in the country’s north-eastern Tete province had contracted the disease. This marks the second imported case of wild poliovirus in southern Africa this year, following an outbreak in Malawi in mid-February.
So far, one case in Mozambique – the country’s first since 1992 – has been detected. The virus was found in a child who began experiencing onset of paralysis in late March. Genomic sequencing analysis indicates that the newly confirmed case is linked to a strain that had been circulating in Pakistan in 2019, similar to the case reported in Malawi earlier this year.
The case in Mozambique and the earlier one in Malawi do not affect Africa’s wild poliovirus-free certification because the virus strain is not indigenous. Africa was declared free of indigenous wild polio in August 2020 after eliminating all forms of wild polio from the region.
“The detection of another case of wild polio virus in Africa is greatly concerning, even if it’s unsurprising given the recent outbreak in Malawi. However, it shows how dangerous this virus is and how quickly it can spread,” said Dr Matshidiso Moeti, World Health Organization Regional Director for Africa. “We are supporting southern African governments to step up the polio fight including carrying out large-scale, effective vaccination campaigns to halt the virus and protect children from its damaging impact.”
Further investigations are underway in Mozambique to determine the extent of the risk posed by the new wild poliovirus case and the targeted responses needed. Preliminary analysis of samples collected from three contacts of the newly-detected case were all negative for wild poliovirus type 1.
Mozambique recently carried out two mass vaccination campaigns – in response to the Malawi outbreak – in which 4.2 million children were vaccinated against the disease. Efforts are currently underway to help strengthen disease surveillance in Malawi, Mozambique, Tanzania, Zambia and Zimbabwe. The five countries will continue with mass vaccinations, with plans to reach 23 million children aged five years and below with the polio vaccine in the coming weeks.
Globally, wild poliovirus is endemic only in Afghanistan and Pakistan. Polio is highly infectious and largely affects children younger than five years. There is no cure for polio, and it can only be prevented by immunization. Children across the world remain at risk of wild polio type 1 as long as the virus is not eradicated in the last remaining areas in which it is still circulating.
African health ministers seek ways to bolster response
African health ministers gathered today to seek ways of ramping up measures to halt the outbreak of Wild Poliovirus Type 1 in southern Africa, where the virus has been detected in two countries and a large-scale multi-country vaccination campaign is underway.
The ministers from Malawi, Mozambique, Tanzania, Zambia and Zimbabwe met on the side-lines of the 22—28 May World Health Assembly in Geneva with World Health Organization (WHO) officials, representatives from the Bill and Melinda Gates Foundation, United States Centers for Disease Control and Prevention, Rotary International and UNICEF. They discussed the recent wild polio outbreaks as well as the ongoing efforts to end vaccine-derived poliovirus in Africa.
Following the wild poliovirus outbreak in Malawi in February, health workers have so far administered more than 23 million doses of vaccines to children under 5 in the five southern Africa countries. On 18 May, Mozambique also confirmed a case of wild poliovirus. The two cases are linked to a wild poliovirus strain that had been circulating in Pakistan in 2019.
WHO and partner organizations are supporting the five southern Africa countries coordinate and carry out rapid and high-quality vaccination campaigns, which are essential in defeating the virus. In addition to the vaccination drives, the five countries have also bolstered disease surveillance to detect and effectively respond to the virus.
“Until the world has halted transmission of all forms of polio, all countries remain vulnerable to outbreaks,” said Dr Matshidiso Moeti, WHO Regional Director for Africa. “Every child must be reached. This requires strong planning, strong implementation, strong monitoring.”
Dr Moeti also acknowledged that there were competing health priorities, especially in the context of the COVID-19 pandemic and appreciated the high-level political commitment by the countries responding to wild poliovirus in the region.
The detection of wild poliovirus in Malawi and Mozambique does not affect Africa’s wild poliovirus-free certification because the virus strain is not indigenous. Africa was declared free of indigenous wild polio in August 2020 after eliminating all forms of wild polio from the region.
Wild poliovirus transmission remains at an all-time low, with only six cases reported globally in 2021. Importation of any case must be treated as a serious concern and high-quality response efforts to reach every child with polio vaccine are critical to prevent further spread.
Wild poliovirus type 1 is currently endemic only in Afghanistan and Pakistan. The poliovirus is highly infectious and largely affects children younger than five years. The disease has no cure, can cause lifelong paralysis, and can be prevented only by immunization.
- Courtesy: WHO Africa Region