Dhaka: Although vaccines need to be stored at cold temperature to ensure its effectiveness, a new study by International Centre for Diarrhoeal Disease Research, Bangladesh (icddr,b) has found that oral cholera vaccine is safe without refrigeration, which will help distribute the vaccine easily in the country’s rural areas.

A study in the country this year showed that the affordable oral cholera vaccine Shanchol is still safe and stimulates significant immune responses even when stored at higher temperature.

The findings of the study, which were recently published in international journal Vaccine, revealed that Shanchol, the first licensed oral cholera vaccine developed by the International Vaccine Institute, do not require to be refrigerated during its distribution.

The icddr,b study tested the ability of Shanchol to stimulate immune responses having been stored for two weeks under standard cold conditions (2-8°C) or at 25°C, 37°C or 42 °C. Storage at higher temperatures had no negative impact on the vaccine’s ability to stimulate protective immune responses or its safety.

According to icddr,b scientists, since the oral cholera vaccine need not to be stored in cold storage, the vaccine will be easier to distribute, vaccination costs will be lower and major logistical challenges to vaccine delivery will be removed.

‘This is the first report to show Shanchol’s stability at elevated temperatures and that its safety and immunogenicity profiles are not altered by high temperatures of storage,’ Dr Firdausi Qadri, icddr,b emeritus scientist who is coordinating cholera vaccine studies, commented in the study:

Over the last 8 years, Dr Qadri and her team have been working on different aspects of the oral cholera vaccine and have facilitated studies that have utilised over 5,00,000 doses of this vaccine in the country.

Dr Qadri said these studies have generated encouraging data on feasibility and effectiveness of Shanchol when used in Bangladesh in collaboration with facilities of the EPI programme of the government.

Shanchol proved highly effective when used during cholera outbreaks in different countries including Guinea in 2012. With the vaccine having proven effective across the world, the WHO began stockpiling Shanchol in 2013.

Another icddr,b study conducted in 2011 in Bangladesh showed that mass vaccination with Shanchol could be feasibly delivered to a high-risk endemic population through an existing national immunisation delivery system.