Experts call for reactivation of national yellow fever surveillance system

MEDICAL practitioners have called for reactivation of a national yellow fever surveillance system which could help to determine yellow fever vaccination coverage in Nigeria.

In addition, Dr Bamidele Iwalokun, a Medical Researcher and Dr Adegboyega Oyefabi, a Consultant Public Health Physician, proffered the health system responses to tackle yellow fever virus challenges in the country.

The experts spoke in separate interviews with the News Agency of Nigeria (NAN) against the backdrop of the recent outbreak of the scourge in Bauchi State.

NAN reports that as at Sept. 9, there were 34 suspected cases of the scourge with samples taken from Bauchi, Alkaleri, Toro, Tafawa Balewa, Dass and Ganjuwa Local Government Areas of Bauchi State.

NAN also reports that 34 samples taken from six local government areas of the state were sent to Abuja for confirmation.

Iwalokun, also Head, Immunology and Vaccinology Research Department, Nigerian Institute of Medical Research (NIMR), Yaba, Lagos, said every state should make efforts to comply with measles vaccine and yellow fever concurrent vaccination at age nine and12 months.

“This can only be achieved if we have adequate yellow fever vaccine in our primary healthcare centres.

“The Federal Ministry of Health, National Primary Health Care Development Agency (NPHCDA), needs to work together and strengthen collaboration with WHO and GAVI to get an adequate supply of the yellow fever vaccine for the country.

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“Currently, there is no specific treatment for yellow fever. Infected patients are treated symptomatically.

“What we have is prevention, by given a yellow fever vaccine through routine immunisation or catch-up vaccination or reactive vaccination.

“Routine is the yellow fever vaccine given to a child aged between nine and 12 months.

“While catch-up is for those who missed routine vaccination aged between 12 months and 60 years and are still lacking immunity against yellow fever,” Iwalokun said.

The medical researcher said that there were three major health system responses to tackle yellow fever virus challenges in Nigeria.

According to him, first is the World Health Organisation (WHO)’s recommendation that yellow fever vaccine should be given concurrently with the measles virus at age nine and 12 months through routine vaccination.

“Secondly, the implementation of the International Health Regulation of 2005, which expect every country to have a surveillance system in place and report the case of yellow fever to WHO.

“While also ensuring that every traveller from yellow fever virus endemic counties has a valid yellow card.

“The third one is the establishment of the Eliminate Yellow Fever Epidemics (EYE) strategy in Abuja, Nigeria in 2016, and the goal is to eliminate yellow fever epidemics by 2026,” Iwalokun said.

He said that researches were needed to develop new technology of making yellow fever vaccine as “the egg culture method of making the live attenuated yellow fever virus vaccine.”

“Yellow fever virus vaccine is gradually becoming inadequate to meet the global needs of the yellow fever vaccine to contain epidemic via reactive immunisation,” the medical researcher said.

He said that Nigeria was among the 35 African countries where yellow fever was endemic and the risk was high.

“The symptoms of yellow fever virus infection include high fever, which resolves in 85 per cent of cases, jaundice due to a viral attack of the liver and kidney damage.

“Deaths often occur in 50 per cent of cases with a severe manifestation of yellow fever virus infection,” Iwalokun said.

Also, Oyefabi, who works with the College of Medicine, Kaduna State University, Kaduna, said that eradication of yellow fever in Nigeria had been a challenge because of the wildlife, especially Monkey, reservoirs of its infection.

He listed how the transmission of this viral haemorrhagic fever in Nigeria could be prevented and controlled.

According to him, the prevention and control of this deadly disease in Nigeria include Yellow fever vaccination, space spraying and international health regulation.

“Yellow fever is a complete vaccine-preventable disease and a single shot of the vaccine will protect for a lifetime.

“Yellow fever vaccine is part of the Nigeria routine immunisation schedule given to infants at nine months.

“Yellow fever vaccine is available for free in all primary healthcare centres in Nigeria as part of the routine immunisation schedule.

“We should ensure that our under-five children are fully vaccinated against the vaccine-preventable diseases including Yellow fever vaccine,’’ Oyefabi said.

The consultant physician said apart from the vaccination, the public should maintain good environmental sanitation by keeping their surroundings clean, free of stagnant water to discourage the breeding places of mosquitoes.

He said: “There should be an elimination of the domestic breeding sites by the destruction of empty containers such as empty cans, old tyres, bottles, jars, among others near household.

“There should be clearing of bushes and drainage channels to maintain free water flow, and space, spraying of the affected area during an epidemic with appropriate insecticide to reduce the load of the biting Aedes mosquito.

“This should be done at the Yankari Game Reserve and other locations where this current epidemic had been reported.

“For optimal result, the spray should be done when these Aedes mosquitoes are at the highest peak of activity between 5.00 p.m and 7:45 pm. A repeat spray can be done after seven to 10 days’ interval.’’

Oyefabi also suggested that personal protective measures should be observed by individuals just as in malaria control, including the use of insecticide-treated nets, insecticide spray at night and protective clothing to prevent mosquito bites.

The expert said: “The yellow fever infection along with cholera, plague and smallpox are diseases subject to the International Health Regulation (IHR).

“An incident of yellow fever should be reported to the World Health Organisation through a reporting network from the affected local government health office (Disease surveillance and notification officer).’’

NAN