Highly targeted interventions may reduce future cholera outbreaks

Two major vaccination campaigns have been implemented since January as part of the global effort to reduce cholera by 90% by 2030, according to WHO.

In sub-Saharan Africa, more than 2 million people are expected to receive the oral cholera vaccine. In Yemen, which is experiencing what the agency described as the world’s largest cholera outbreak in history, more than 4.6 million doses of the vaccine have been secured from the global stockpile to target cholera hotspots across the country.

Although these vaccination drives are part of a greater effort in the fight against cholera, targeted interventions aimed at those with increased risk could potentially help reduce future outbreaks in countries where the disease is endemic.

New study findings recently published in the Journal of Infectious Diseases present a potential strategy to contain and control future outbreaks. Andrew S. Azman, PhD, research associate in the department of epidemiology at the Johns Hopkins Bloomberg School of Public Health, and colleagues documented GPS coordinates of households with reported cholera cases from 2011 to 2014 in Chad and the Democratic Republic of the Congo. They determined that within the first 5 days of a cholera case being reported, the risk for infection extends across a 200-m zone from the household where the case originated. The most elevated risk was observed within 100 m of the cholera case’s household and within the first few days after diagnosis.

In a second study published in the Public Library of Science, Azman and colleagues analyzed the impact targeted interventions— such as improving water, sanitation and hygiene and administering oral cholera vaccines and prophylactic antibiotics— had on the zones of increased risk. They found that understanding the radius of risk and beginning immediate intervention to surrounding neighbors may potentially stymie outbreaks and shorten epidemics.

“Cholera risk can be highly focal during outbreaks,” Azman told Infectious Disease News. “If public health systems are agile enough to quickly target neighbors of cholera cases with effective cholera interventions like water improvements and oral cholera vaccine, highly targeted approaches may be a highly efficient way to quickly bring outbreaks to an end.” – by Marley Ghizzone

References:

Azman AS, et al. J Infect Dis.2018;doi:10.1093/infdis/jiy283.

WHO. Fighting the world’s largest cholera outbreak: oral cholera vaccination campaign begins in Yemen. http://www.emro.who.int/yem/yemen-news/oral-cholera-vaccination-campaign-in-yemen-begins.html. Accessed May 14, 2018.

Aljazeera. Key facts about the war in Yemen. https://www.aljazeera.com/news/2016/06/key-facts-war-yemen-160607112342462.html. Accessed May 14, 2018.

Finger F, et al. PLoS Medicine. 2018;doi:10.1371/journal.pmed.1002509.

Disclosures: Azman reports no relevant financial disclosures. Please see the study for all other authors’ relevant financial disclosures.