The oral cholera vaccine Shanchol™ when stored at elevated temperatures maintains the safety and immunogenicity profile in Bangladeshi participants.
BACKGROUND
The oral cholera vaccine (OCV), Shanchol™ has shown protective efficacy lasting up to 5 years, however, requirement for a cold chain limits its use in resource poor settings. The study was conducted to determine the safety and immunogenicity of Shanchol in adult participants in Bangladesh when stored at elevated temperatures.


METHODS
The study was conducted in Mirpur, Dhaka. Four groups of healthy adult participants received two doses of Shanchol™, kept under standard storage temperature (Group A; 2-8°C) or at elevated temperatures (Group B, 25°C; Group C, 37°C; Group D, 42°C) for 14 days, respectively. Vaccine specific antibody responses were determined.


FINDINGS
145 participants were assigned to each group. Adverse events were mild not differing among groups. Vaccine stored at elevated temperatures remained stable with cumulative LPS content within admissible limits. Vibriocidal antibody responses were observed in all groups after each dose of vaccine at day 7 and 21 compared to pre-immune levels (P<0.001). Four-fold increases to Vibrio cholerae O1 Ogawa were observed at day 7 and/or day 21 after vaccination in the standard temperature and the three elevated temperature groups, with responder rates of; 76% (95% CI LB; 70%), 80% (95% CI LB; 74%), 69% (95% CI LB; 63%), and 74% (95% CI LB; 68%) in Groups A-D, respectively (P=0.240). Responses were also seen in all groups to V. cholerae O1 Inaba and V. cholerae O139 and in LPS specific IgA response to V. cholerae O1 antigens.


INTERPRETATION
This is the first report to show that the OCV is stable at elevated temperatures, and the safety and immunogenicity profiles are not altered. This information will help formulate global policies for use of the vaccine at higher temperatures, resulting in easier distribution and vaccination costs and decrease logistical challenges to vaccine delivery.


FUNDING
Bill & Melinda Gates Foundation.


TRIAL REGISTRATION
Clinical Trials.gov number NCT01762930.
['Saha|Amit|A|', 'Khan|Arifuzzaman|A|', 'Salma|Umme|U|', 'Jahan|Nusrat|N|', 'Bhuiyan|Taufiqur Rahman|TR|', 'Chowdhury|Fahima|F|', 'Khan|Ashraful Islam|AI|', 'Khanam|Farhana|F|', 'Muruganandham|Sundaram|S|', 'Reddy Kandukuri|Sreeramulu|S|', 'Singh Dhingra|Mandeep|M|', 'Clemens|John D|JD|', 'Cravioto|Alejandro|A|', 'Qadri|Firdausi|F|']
D000328:Adult D000907:Antibodies, Bacterial D000917:Antibody Formation D001459:Bangladesh D002771:Cholera D022121:Cholera Vaccines D005260:Female D006358:Hot Temperature D006801:Humans D007070:Immunoglobulin A D008297:Male D012034:Refrigeration D041241:Vibrio cholerae O1 D055815:Young Adult
Oral cholera vaccine Shanchol™ Cold chain Immune response Thermal stability