The Commission on Human Medicines (CHM) has issued a series of recommendations to minimise risk with yellow fever (YF) vaccine (Stamaril) following a number of reports of YF vaccine-associated viscerotropic disease (YEL-AVD) and neurotropic disease (YEL-AND).
Key recommendations include updated contraindications and precautions and standardised risk-benefit evaluation procedures for UK vaccination centres.
Recent fatal cases of YEL-AVD in the UK prompted the CHM to convene an Expert Working Group to consider the risk-benefit balance of the vaccine, as well as risk factors for serious adverse reactions, and the measures in place in the UK to minimise risks.
The review considered published data and adverse events reported to the Medicines and Healthcare products Regulatory Agency and the manufacturer and through the National Travel Health Network and Centre (NaTHNaC) and Health Protection Scotland (HPS).
Cases of YEL-AND have been reported in primary vaccinees, with an onset within 30 days of vaccination. The risk appears to be higher in people older than 60 years and younger than nine months of age (including infants exposed to vaccine through breastfeeding), although cases have also been reported in other age groups.
YEL-AND may manifest as high fever with headache that may progress to include confusion, lethargy, encephalitis, encephalopathy, and meningitis. Other features include convulsions, Guillain-Barré syndrome and focal neurological deficits.
Cases of YEL-AVD (formerly described as febrile multiple organ-system failure) have also been reported, some of which have been fatal. In most cases reported, the onset of signs and symptoms was within 10 days of vaccination.
Initial signs and symptoms of YEL-AVD are non-specific and may include pyrexia, myalgia, fatigue, headache and hypotension, potentially progressing to liver dysfunction with jaundice, muscle cytolysis, thrombocytopenia and acute respiratory and renal failure.
Further information is available here.