Azfar Hossain

1 Introduction A new outbreak of cholera was declared in September 2022 by Haiti's Ministry of Health when culture-confirmed cases were identified for the first time in the country since 2019. Within 2 months, this new outbreak had resulted in nearly 12,000 suspected cases of cholera.

The Centers for Disease Control and Prevention (CDC) reported in January 2024 that US syphilis cases have increased by almost 80 percent since 2018, highlighting the magnitude of a sexually transmitted infection (STI) epidemic that costs more than one billion dollars annually. Although a pill available at a very low cost (around $24 for 20 pills) could protect many of my patients from these STIs, our health care system is at risk of fumbling its implementation.

Summary Background Contact tracing is used for multiple infectious diseases, most recently for COVID-19, but data regarding its effectiveness in disease control are scarce. To address this knowledge gap and inform public health decision making for COVID-19, we systematically reviewed the existing literature to determine the effectiveness of contact tracing in the control of communicable illness.