The World Health Organization (WHO) has recommended that the target area for Ebola vaccine administration should be expanded after a rise in the number of cases over the last four weeks.

A two-ring vaccination approach is currently being used in The Democratic Republic Of Congo (DRC) following an outbreak in August last year. More than 110,000 people were offered the vaccine under the immunisation programme as they were deemed likely to become infected.

WHO’s Strategic Advisory Group of Experts (SAGE) is now calling for the two-ring strategy to be expanded to three rings. It also suggested a geographic vaccination strategy that would target everyone in one location, rather than only those thought to be at risk, noted Reuters.

Response teams are currently providing Merck’s rVSV-ZEBOV-GP vaccine.

“These recommendations account for ongoing insecurity and incorporate feedback from experts and from the affected communities that will help us continue to adapt the response.”

In order to avoid running out of vaccine supplies, SAGE recommended the use of smaller doses of Merck’s vaccine and the release of a second experimental vaccine developed by Johnson & Johnson (J&J).

WHO director-general Dr Tedros Adhanom Ghebreyesus said: “We know that vaccination is saving lives in this outbreak. We also know that we still face challenges in making sure the contacts of every case receive the vaccine as soon as possible.

“These recommendations account for ongoing insecurity and incorporate feedback from experts and from the affected communities that will help us continue to adapt the response.”

WHO also issued a warning to boost vaccination efforts to address the outbreak of measles in Europe.

In the first two months of this year, 34,300 people have been infected with measles across 42 countries in WHO’s European region, including reports of 13 measles-related deaths across Albania, Romania and Ukraine.

In a statement, WHO said: “There is no specific antiviral treatment for measles. Vaccination is the only way to prevent the disease. High vaccination coverage of at least 95% with two doses of measles vaccines in all population groups and age cohorts at a national level and in all districts is crucial to elimination.”

Earlier this month, Merck announced increased production of its measles vaccine in the US to meet the rising demand following an outbreak in the country.