Accra, May 17, GNA – The World Health Organisation (WHO) says the 10 years yellow fever ‘booster’ vaccination is not necessary.
An article published in WHO’s Weekly Epidemiological Record, obtained by the Ghana News Agency on Friday reveals that the Organisation’s Strategic Advisory Group of Experts on immunisation (SAGE) has reviewed the latest evidence and concluded that a single dose of vaccination is sufficient to confer life-long immunity against yellow fever disease.
It said since yellow fever vaccination began in the 1930s, only 12 known cases of yellow fever post-vaccination have been identified, after 600 million doses have been dispensed.
The article said evidence showed that among this small number of “vaccine failures,” all cases developed the disease within five years of vaccination, which demonstrates that immunity does not decrease with time.
The WHO noted that yellow fever is an acute viral haemorrhagic disease transmitted by infected mosquitoes that is endemic to 44 countries in tropical areas of Africa and the Americas.
It said infection with the yellow fever virus causes varying degrees of disease, from mild symptoms to severe illness with bleeding and jaundice and fatal outcomes.
The WHO article said there are an estimated 200,000 cases of yellow fever worldwide each year and about 15 per cent of people infected with the disease progress to a severe form of the illness.
It said the vast majority of reported cases and deaths occur in sub-Saharan Africa; declaring that in endemic regions of Africa, yellow fever natural immunity is acquired with age, putting children at highest risk of infection.
The WHO publication said over the past two decades, the number of yellow fever cases worldwide has increased due to declining population immunity to infection, deforestation, urbanisation, population movements and climate change.
It said vaccination is considered to be the most important and effective measure against yellow fever; protective immunity develops within 30 days for 99 per cent of people receiving the vaccination and for routine immunisation programmes in Africa, home to 31 of the 44 yellow-fever endemic countries, the vaccine costs about $0.82 per dose.
SAGE is the principal advisory group to WHO for vaccines and immunisation.
It is charged with advising WHO on overall global policies and strategies, ranging from vaccines and technology, research and development, to delivery of immunisation and its linkages with other health interventions.
SAGE is concerned with all vaccine-preventable diseases including childhood vaccines and immunisation.