With support from American and international agencies, the government of the Republic of Congo has launched an emergency response plan, with nationwide vaccination starting on Friday, to deal with the polio outbreak that has killed scores of people in and around the central African country’s second largest city, Pointe Noire.

The World Health Organization (WHO) said on Tuesday that184 cases of acute flaccid paralysis and 85 deaths have been reported from sites in and near the port city of Pointe Noire, the center of the acute poliomyelitis outbreak. Most of the cases have been in the city, with 5 reported from Niari, 2 from Bouenza, 2 from Kouilou, and 1 from Brazzaville.

The last recorded case of indigenous polio in Congo was reported in 2000.

Polio is an acute disease caused by a virus that attacks the central nervous system, with symptoms ranging from a mild non-paralytic infection to severe paralysis within hours.

It usually affects children under the age of five, but in this outbreak, most of the reported cases and deaths have been among people aged over 15, said the WHO.

Tests have so confirmed that four cases were caused by wild poliovirus type 1, and that the strain is most closely related to that circulating in neighbouring Angola.

The emergency response plan has been launched with the help of key partners such as the WHO, UNICEF and the US Centers for Disease Control and Prevention (CDC).

The recent progress toward polio eradication in Nigeria, where there has been a 98 per cent reduction in new cases in 2010 compared to 2009, means that acting quickly to stop fresh outbreaks and spreading in central Africa is a top disease control priority, said the WHO.

The first batch of vaccinations will start on Friday 12 November, will use the monovalent oral polio vaccine type 1 (mOPV1), and will cover at least one million people in Porte Noire, the department of Kouilou, along the country’s coastline, and also another 600,000 in the province of Cabinda in neighbouring Angola.

Vaccination in the rest of the Congo will start on the 18th November, also using mOPV1, according to the latest WHO update, and will be followed by two further nationwide rounds.

Exactly which groups are to be vaccinated will depend on how the outbreak develops, and further bordering countries may be included.

Meanwhile new cases continue to be reported.

Central African countries should be on the alert and increase their surveillance to rapidly detect and report cases of acute flaccid paralysis (AFP), urged the WHO, who said they should also “address any gaps in polio immunization coverage to minimise the consequences of a poliovirus introduction”.

People travelling to and from the Republic of Congo, and its neighbours Angola and the Democratic Republic of Congo, should also be fully protected against polio by vaccination, in line with the organization’s International Travel and Health publication, said the WHO.

Rod Curtis, a communications officer for the WHO Global Polio Eradication Initiative said that due to political instability, polio immunization campaigns have not taken place in the Republic of Congo for the last 15 years.

“People who were not vaccinated are vulnerable to the polio virus,” Curtis told IRIN, the UN’s humanitarian news agency.

While improving water and sanitation helps in the longer term to stop the virus spreading, the fastest and most effective method in an emergency is mass vaccination, both in the country and it neighbours, because of population movement, he added.

“If all African countries continue to immunize children and maintain surveillance systems, we’ll witness a serious decline in the virus,” said Curtis.

Sources: WHO, IRIN.

Written by: Catharine Paddock, PhD