The disease has also largely been controlled it in Africa and Asia. Wild enteroviruses coincidentally present in the gut may also interfere, especially in the tropics. Live vaccination mimics natural infection with good immunity including IgA in the gut. This vaccine is used in RSA, USA and most other countries. It is very important to maintain 'cold chain' when storing and distributing vaccine as it may lose potency.
Much antigen is required which makes the vaccine expensive.
Most infections are silent. Viraemia may lead to degrees of involvement of secondary 'target organs' and clinical symptoms and signs related to those organs. Viral meningitis resolves spontaneously without treatment but bacterial meningitis is a medical emergency requiring treatment. These notes were prepared by Anthony Keen for Virology Lectures to 3rd Year Medical Students in the Department of Medical Microbiology , University of Cape Town.