Dengue vaccine: come let's fight the menace.

Although dengue has a global distribution, the World Health Organization (WHO) South-East Asia region together with Western Pacific region bears nearly 75% of the current global disease burden. Globally, the societal burden has been estimated to be approximately 528 to 1300 disability-adjusted life years (DALY) per million to populations in endemic regions Dengue is believed to infect 50 to 100 million people worldwide a year with half a million life-threatening infections requiring hospitalization, resulting in approximately 12,500 to 25,000 deaths. Despite being known for decades and nearly half the world's population is at risk for infection with as many as 100 million cases occurring annually, the pitiable state is that we still have no antiviral drugs to treat it and no vaccines to prevent it. In recent years, however, the development of dengue vaccines has accelerated dramatically in tandem with the burgeoning dengue problem with a rejuvenated vigour. However, recent progress in molecular-based vaccine strategies, as well as a renewed commitment by the World Health Organization (WHO) to co-ordinate global efforts on vaccine development, finally provides hope that control of this serious disease may be at hand. Today, several vaccines are in various stages of advanced development, with clinical trials currently underway on 5 candidate vaccines. Trials in the most advanced stages are showing encouraging preliminary data, and the leading candidate could be licensed as early as 2015.

Human papillomavirus vaccine: a boon or curse.

Cervical cancer is the second most common cancer among women worldwide, with about 493,000 new cases diagnosed annually. Of 274,000 deaths due to cervical cancer each year, more than 80% occur in developing countries, and this proportion is expected to increase to 90% by 2020. Up to 70% of sexually active women will become infected with human papilloma virus (HPV) during their lifetime. Even though screening reduces the risk of cervical cancer, it does not prevent HPV infection or development of precancerous lesions which need careful follow-up and often need excision. It was observed in a study, pre-adolescent vaccination alone reduced cancer incidence by 44% and was more effective than screening alone. A combined approach of pre-adolescent vaccination and screening of adult women was more effective than either alone. The high probability of acquiring HPV infection once, one has become sexually active raises the question of whether the vaccine will be effective if given to girls who have already been infected with HPV type 16 or 18. In April 2010, The Indian parliament's Standing Committee on Health, began probing the use of HPV vaccines in 2 states after the reported deaths of 7 girls, and concluded that "safety and rights of children were highly compromised and violated." Though the question of immunization of older girls and women deserves attention, from a public health perspective, the first priority in resource-poor settings would be to vaccinate young adolescent girls.