Soil Transmitted Helminths (STH) are among the most common infections in the world today. The World Health Organization (WHO) recommends mass administration of deworming medicine as a single routine annual dose to all school age children (SAC)(age 5-16 years) in countries where prevalence of Soil Transmitted Helminthic Infections (STHI) is > 20% as a safe public health intervention that promotes healthy growth (Category 2 Recommendation). Pakistan is classified as a low burden community with a reported prevalence of STHI <50%, however,routine deworming is not a policy in Pakistan. Currently, Pakistan is also facing a huge burden of malnutrition in all age groups especially in population belonging to low socioeconomic group. Incidentally, worm infestation by STH also occurs in this group due to associated lack of hygiene and poor living conditions. The coexistence of even moderate STH infections can cause or aggravate malnutrition. The urban slums of Karachi provide environmental, social and behavioral conditions that favor both STH infections and a risk of under nutrition. It is unknown if administering routine dose of deworming medicine to SAC as per WHO recommendation will contribute to improvement in indicators of nutrition status in Pakistani children living in urban slum conditions by eliminating worm infection.Therefore, this study is being conducted to determine the effect of deworming on weight of School Age Children aged between 5 to 16 years.

A randomized control trial will be conducted in an urban slum of Karachi. Eligible 5 to 16 year old school age children will be enrolled after parental consent. The calculated total sample size is n= 258. Subjects will be visited at home by researcher and background information, risk factor presence and baseline measurements of weight, Mid Upper Arm Circumference (MUAC) and tricep skinfold thickness (TSF) will be measured. The intervention arm will be administered a single dose of chewable Albendazole 400 mg and the placebo arm will receive 400 mg chewable calcium tablets. The weight, MUAC and TSF will be measured again after 8 weeks to determine the change if any. The selection of locality and allocation of intervention will be done using simple random sampling and computer generated random numbers.

Inclusion Criteria:

• Aged 5 - 16 years, Healthy, Able to chew/swallow tablets

Exclusion Criteria:

• Acutely ill
• Previous deworming dose < 6 months ago
• Intellectually challenged or physical condition interfering with measurement of primary outcome variables

If chosen for inclusion in meta analysis, Individual Participant Data (IPD) on outcome variables may be shared