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Biomedical subjects

Jay Wenger

Publications and source records attributed to Jay Wenger.

8 recordsLinked to original sources

New strategies for the elimination of polio from India.

The feasibility of global polio eradication is being questioned as a result of continued transmission in a few localities that act as sources for outbreaks elsewhere. Perhaps the greatest challenge is in India, where transmission has persisted in Uttar Pradesh and Bihar despite high coverage with multiple doses of vaccine. We estimate key parameters governing the seasonal epidemics in these areas and show that high population density and poor sanitation cause persistence by not only facilitating transmission of poliovirus but also severely compromising the efficacy of the trivalent vaccine. We analyze strategies to counteract this and show that switching to monovalent vaccine may finally interrupt virus transmission.

Child↗

Polio eradication in India: current status.

India has reached the final stage of polio eradication. The polio partnership in India, under the leadership of the Government of India, mounted tremendous response to the outbreak. The progress since 2003 is the most significant in the history of polio eradication in India. Surveillance sensitivity was increased to reach the goal for polio eradication. Since nearly all polio cases now occurring in India are caused by type 1 poliovirus in children, monovalent oral polio vaccine type 1 (mOPV1) was introduced in select high-risk districts of UP, Bihar and Mumbai-Thane during the April and May 2005 National Immunisation Days and the June and August 2005 in 6 sub-national immunisation rounds. Strategies were also being implemented to improve the impact of supplementary immunisation activities in the high-risk areas. As a result of supplementary immunisation activities targeted using surveillance data, India has made striking progress towards polio eradication.

Child↗

Detecting polio through surveillance for acute flaccid paralysis (AFP).

Accurate surveillance for polio is essential for eradication. Surveillance systems for polio has been developed under the guidance of the global polio eradication initiative. Surveillance of cases of acute flaccid paralysis among children less than 15 years of age is a key component for a well functioning polio surveillance system. The surveillance system works through a network of surveillance medical officers, the responsibility of them lies in assisting the health services departments of all states and maintaining a network of acute flaccid paralysis reporting sites and rapidly investigating the cases. Surveillance activities begin when a child comes in contact with a healthcare provider who in turn informs the officer in charge of acute flaccid paralysis surveillance. The goal of the polio network laboratories is to provide accurate and timely results of wild poliovirus detection in stool samples of cases of acute flaccid paralysis. Strong linkages have been established between the acute flaccid paralysis surveillance system and the laboratory network. Laboratories complete poliovirus isolation and if poliovirus is isolated, these are submitted for intratypic differentiations. Acute flaccid paralysis surveillance in India has demonstrated that the eradication activities implemented in India led to dramatic reduction and restriction in the number of cases and geographic spread of poliovirus transmission.

Acute Disease↗

Routine immunisation in India.

Vaccine preventable diseases have been reduced in the country since the routine immunisation programme started in 1978 as the Expanded Programme on Immunisation, then in 1985 renamed as Universal Immunisation Programme. Re-emergence of some vaccine preventable disease is a concern to all and the Government of India has launched a new multiyear plan to strengthen the routine immunisation. A number of recommendations was made to address the weaknesses in the programme. Some newer initiatives were also made under the multiyear plan and National Rural Health Mission to strengthen the routine immunisation. The general practitioners can play a positive role while immunising children as per Universal Immunisation Programme. Routine immunisation is one of the key components of polio eradication.

Child↗

Estimating the Haemophilus influenzae type b (Hib) disease burden and the impact of Hib vaccine in Fiji.

AIMS: To estimate Haemophilus influenzae type b (Hib) disease burden in Fiji in children under the age of 5 years (under-5s) prior to vaccine introduction. To compare estimates from WHO's Hib rapid assessment tool (RAT), with that from decline in disease after vaccine introduction. METHODS: Laboratory data (meningitis), hospitalization and mortality data (pneumonia and meningitis) before and after Hib vaccine introduction were collected. The RAT protocol provides two independent estimates of pre-vaccine disease burden (one based on meningitis incidence laboratory data and the other based on mortality statistics). A third estimate uses the decline in disease following vaccine introduction. RESULTS: The decline in meningitis hospitalizations implies a pre-vaccine Hib meningitis incidence of 66 per 100,000 in under-5s. This compares with a pre-vaccine RAT estimate of Hib meningitis incidence of 84 per 100,000 (for 1992-1993). The RAT estimated the total annual pre-vaccine Hib burden (meningitis plus pneumonia) at 476 cases and 36 deaths per year ("meningitis incidence method") and 70 cases and 5 deaths ("child mortality method"). Hib vaccine led to declines of 32% (95% confidence interval (CI)=11-48%), and 78% (95% CI=22-94%) for all under-5s meningitis hospitalizations and deaths, respectively. There was no similar consistent decline in pneumonia hospitalizations or deaths after vaccine introduction, except for a statistically significant reduction in pneumonia mortality in children aged under 1 year. CONCLUSIONS: Hib disease constitutes an important burden on the health of Pacific children that can be rapidly reduced with Hib vaccine. In this setting, routine morbidity statistics (comparing pre-and post-vaccine) provided an estimate of Hib meningitis burden which is broadly similar to that of the Hib RAT, suggesting that both might be valid ways to estimate Hib meningitis incidence. However, Hib pneumonia burden could not be estimated from routine statistics.

Animals↗

The beneficial impact of Hib vaccine on disease rates in New Zealand children.

AIM: To examine the impact of Haemophilus influenzae type b (Hib) vaccine on the burden of Haemophilus influenzae (Hi) disease in New Zealand children aged under five years (under-5s). METHODS: Analysis of national mortality, hospitalisation, laboratory, and notification data. RESULTS: The introduction of Hib vaccine in 1994 led to a 92% decline (95%CI = 89 94%) in the hospitalisation rate of Hi meningitis for under-5s (1995 2000 compared to 1988 1993). Pre-vaccine, the Hi meningitis hospitalisation rate was 27 per 100 000 in the under-5s and this declined to 2 per 100 000. Even though Hi meningitis declined in all ethnic groups (eg down to 3 per 100 000 among Maori), there was a worsening of equity with the proportion of children hospitalised with Hi meningitis who were Maori increasing from 23% to 40% of all cases. The rate of epiglottitis hospitalisations also declined substantially (by 94%, 95%CI = 89 - 96%). CONCLUSIONS: Hib vaccination appears to be preventing at least 80 cases of meningitis and 30 cases of epiglottitis every year in under-5s in New Zealand. But the beneficial impact of Hib vaccination has been less for Maori and so there is a need for further improvements in immunisation coverage in those populations with the highest disease burdens.

Child, Preschool↗