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PLoS One. 2014 Jul 1;9(7):e99381. doi: 10.1371/journal.pone.0099381. eCollection 2014.

Safety and immunogenicity of a live oral recombinant cholera vaccine VA1.4: a randomized, placebo controlled trial in healthy adults in a cholera endemic area in Kolkata, India.

Author information

  • 1Department of Epidemiology, National Institute of Cholera & Enteric Diseases, Kolkata, West Bengal, India.
  • 2Society for Applied Studies, Kolkata, West Bengal, India.
  • 3Department of Microbiology, National Institute of Cholera & Enteric Diseases, Kolkata, West Bengal, India.
  • 4Catalyst Clinical Services Pvt. Ltd., Delhi, India.
  • 5Department of Biotechnology, Ministry of Science and Technology, New Delhi, India.
  • 6Institute of Post Graduate Medicine and Research, Chandigarh, India.
  • 7Translational Health Science and Technology Institute, Gurgaon, Haryana, India.



A live oral cholera vaccine VA 1.4 developed from a non-toxigenic Vibrio cholerae O1 El Tor strain using ctxB gene insertion was further developed into a clinical product following cGMP and was evaluated in a double-blind randomized placebo controlled parallel group two arm trial with allocation ratio of 1∶1 for safety and immunogenicity in men and women aged 18-60 years from Kolkata, India.


A lyophilized dose of 1.9×109 CFU (n = 44) or a placebo (n = 43) reconstituted with a diluent was administered within 5 minutes of drinking 100 ml of a buffer solution made of sodium bicarbonate and ascorbic acid and a second dose on day 14.


The vaccine did not elicit any diarrhea related adverse events. Other adverse events were rare, mild and similar in two groups. One subject in the vaccine group excreted the vaccine strain on the second day after first dose. The proportion of participants who seroconverted (i.e. had 4-folds or higher rise in reciprocal titre) in the vaccine group were 65.9% (95% CI: 50.1%-79.5%) at both 7 days (i.e. after 1st dose) and 21 days (i.e. after 2nd dose). None of the placebo recipients seroconverted. Anti-cholera toxin antibody was detected in very few recipients of the vaccine.


This study demonstrates that VA 1.4 at a single dose of 1.9×109 is safe and immunogenic in adults from a cholera endemic region. No additional benefit after two doses was seen.


Clinical Trials Registry-India, National Institute of Medical Statistics (Indian Council of Medical Research) CTRI/2012/04/002582.

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