Yellow Fever Vaccine; its necessity and Risk

• The recent death of UK’s leading Cancer Scientist, following a yellow fever vaccination, has invigorated the debate on the efficacy of vaccines and the ‘vaccine hesitancy’.

• The overall risk of serious side effects of vaccination is very low, but people aged over 60 have about three fold risk of experiencing serious effects.

About Yellow Fever

• Yellow fever is a viral disease commonly found in the tropics caused by a group of virus called flavivirus, which is transmitted by the Aedes aegypti mosquito, the same mosquito that spreads the Zika, Chikungunya and Dengue virus.
• The mosquito becomes infected by biting an infected human or a monkey and the virus is then transmitted to other humans.
• The virus is endemic in tropical areas of Africa and Central and South America.

Symptoms

• Yellow fever is a hemorrhagic fever that can lead to a high fever, muscle pain with prominent backache, headache, shivers, loss of appetite, and nausea or vomiting. 
• In severe cases there might be bleeding into the skin, and the virus can affect the cells of liver and kidneys.

Yellow Fever Vaccination

• Yellow fever vaccine, known as 17D, contains a live attenuated form of the virus.
• It works by activating an immune response from the body against the virus and this response can memorise the infection and thus confers life long immunity.

Vaccine Side-effects

• Though vaccination is an essential strategy to combat yellow fever virus, it can rarely cause severe side-effects.
• The side-effects include headaches, fevers, muscle pain, tiredness, soreness and in very rare cases, infants and older people may develop serious reactions, such as encephalitis, organ failure or anaphylactic shock which may lead to death.

 The Problem of Vaccine Hesitancy in India

• While India is striving to achieve universal immunization, the problem of vaccine hesitancy has contributed to the immunization gap in the country.
• According to WHO, “Vaccine hesitancy refers to delay in acceptance or refusal of vaccination despite availability of vaccination services and occurs along the continuum of full acceptance, including high demand for vaccine, and outright refusal of some or all vaccines”.
• The reasons for hesitancy in India are:
  • Under-confidence (49%)
  • Convenience (18%)
  • Poverty
  • Ignorance
  • Migration
  • Illness of the child at the time of vaccination
  • Rare case of vaccination side effect may trigger fear in that area

Managing the problem of  Vaccine Hesitancy

• The hesitancy at any level can undermine vaccination coverage. So, it is important to understand both the extent and nature of hesitancy at a local level, on a continuing basis.
• Accordingly, a strategy should be developed to increase acceptance and demand for vaccination, which should include:
  • Active hesitancy prevention
  • Ongoing community engagement and trust-building
  • Regular national assessments of concerns
  • Crisis response planning