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Mandatory visits to immunization centers that offer pre-travel Yellow fever vaccine to prospective travelers would be useful for briefing the basics of the biology of the mosquito responsible for Yellow fever spread. Pre- travel knowledge on the day-time rather the nocturnal biting habit of the mosquitoes of Aedes species would prevent from bites of the mosquitoes responsible for the spread of viruses causing Yellow fever, dengue or Chikungunya infection., (Copyright © 2012 Elsevier Ltd. All rights reserved.)

The 17D-derived yellow fever (YF) vaccines have had an excellent record of their safety among millions of recipients. Recently, extensive viral dissemination in seven vaccinees, aged 5-79 years, with just one survivor posed a serious challenge for vaccine manufacturers. Prospective evaluations of yellow fever vaccine bulk suspensions for their viscerotropism and neurovirulence in primates or an alternate animal should minimize identical viral dissemination among prospective recipients of YF vaccines.

While measles, pertussis and tetanus were responsible during the early 1990s for nearly two million deaths in developing countries, no deaths were attributable to them in industrialized countries. More than 96% of global deaths by communicable diseases were also from developing countries. Respiratory infections ranked first in communicable morbidity at all ages. Even though vaccines of bacterial or viral origin or a prophylactic for passive immunization are produced in 24, 16 and 15 developing countries, respectively, none of the developing countries manufactures a plasma-derived prophylactic or biological response modifier. Nearly every country relies on import of one or more vaccines. The suboptimal performance of otherwise meritorious products has been due to faulty vaccine administration practices. Expanding populations, poverty and lack of education, cold-chain defects, and inadequate facilities for transport of vaccines to target populations in remote areas have been responsible for the poor performance of vaccines in the community. Mounting foreign debts and budgetary strains resulting from the care and prevention of AIDS/HIV have considerably strained national and international efforts to offer routine vaccinations in childhood and pregnancy. This dismal situation could be tackled through research to obtain environmentally stable products for prophylactic use and monoclonal antibody formulations for passive immunization, and through international financial and technical support. All countries should exercise some technical control of the quality of imported and indigenous vaccines during their use for curative or prophylactic purposes. The involvement of private clinicians in immunizations would strengthen national efforts for control of communicable diseases including AIDS, but this is not enough if the local factors cited above are not improved.