ICDDR, B study finds cholera vaccine ‘effective’

An ICDDR, B study published in The Lancet has stated that oral cholera vaccine can reduce the hospitalisation and deaths caused by the water-borne disease in Bangladesh.

The diarrhoeal disease research centre says the findings “lend support to the use of the vaccines in routine mass vaccination programmes to help control cholera in endemic countries”.
 
But The Lancet, the world's leading independent general medical journal, called for “due consideration” before devising any strategies in this regard.
 
Public health experts in Bangladesh, however, had earlier warned the government against any move to include cholera vaccine in the routine immunisation drive.
 
“It would be like putting the cart before the horse,” public health analyst Dr Khairul Islam on Thursday said after the publication of the study results.
 
He said water, sanitation and hygiene were still “neglected” in Bangladesh.
 

The country was unable to reach the MDG targets related to water and sanitation, despite achieving several other goals.

The Lancet also commented on the study, saying “oral cholera vaccine is only one part of the larger programme needed to control cholera”.

“It should not supersede efforts to reduce risky behaviours, and to improve sanitation and provide safe drinking water to people living in cholera-endemic areas,” the UK medical journal said.

It said oral cholera vaccines had “great potential” for aiding disease control.

“But due consideration must be given to devising the best strategies for delivery as a mass public health intervention and to any possible threats to successful programme implementation”.

A long-standing controversy

Cholera vaccine has long been a controversial issue in Bangladesh as the ICDDR, B has been trying to push for a vaccine. A botched attempt had been made in the late 1980s.

Public health activists have been demanding an improved water and sanitation system for the country. But budgetary allocation for this crucial sector has been on the decline of late.

The government first spoke of cholera vaccine in 2011 after at least a decade, when it placed an ICDDR, B-backed resolution at the WHO annual meeting in Geneva.

The centre was conducting a feasibility test of an oral cholera vaccine in Mirpur.

Leaders of Health Rights Movement National Committee had said the government had fallen “into the trap of oral cholera vaccine”.

WHO recommended the cholera vaccination in endemic and epidemic settings in 2010 after a devastating cholera outbreak in Haiti.

The Lancet says clean water, sanitation and behaviour change will ultimately be the most critical factors in cholera prevention and control, but these are difficult to implement in many cholera-endemic countries.

Thus, “a more immediate solution is needed”.

This oral cholera vaccine had been shown to be efficacious in earlier trials. But The Lancet welcomed the Bangladesh trial as it showed the “feasibility and effectiveness under real-life conditions”.

The journal said it is a “welcome step towards vaccine deployment in endemic settings”.

‘Disappointing’ behavioural change

The trial included 94, 675 residents assigned to vaccination only, 92, 539 assigned to vaccination and behavioural change involving a hand washing and clean drinking water campaign, and 80, 056 assigned to no intervention.

The results show, at 65 percent vaccination coverage level the incidence of severely dehydrating cholera was reduced by 37 percent in the overall study population, irrespective of their vaccination status.

It decreased by 45 percent in the group that received both vaccination and hand washing-water treatment intervention.

For participants that received the full two doses of the vaccine, the rate of hospitalisation decreased by more than 50 percent.

The Lancet says the hand-washing and chlorinated drinking water programme had “a modest effect” on cholera in the study.

“The difference between the vaccine and behavioural change and the vaccine-only groups might have been caused by chance.

“Because of the importance of behaviour change in reducing the risk of cholera and other diarrhoeal diseases, this small effect is disappointing”.

The journal suggested further efforts to improve hand washing and interventions to ensure access to safe water in cholera-endemic areas.

It also suggested efforts to understand the reasons for “non-compliance with these interventions as this is a crucial component in cholera control”.

The Lancet says, depending on the duration of protection, populations in endemic areas might need to be targeted for vaccination regularly, which could affect the acceptability and uptake of the vaccine.

But it says the vaccine coverage reported by the study “might not be sustainable in repeat and ongoing vaccination campaigns” since achieving high coverage with seasonal vaccination campaigns such as influenza is difficult.

“So careful attention must be paid to community engagement to ensure the success of such a programme.”

More than one billion people are at risk of cholera in endemic countries, with an estimated 2.9 million cases and 95,000 deaths per year.

A further 87,000 cases and 2,500 deaths occur in non-endemic countries.

ICDDR,B says Bangladesh has an estimated 300,000 cases of cholera and 4,500 deaths each year.

Climate change, war, natural disasters, population movement, and urbanisation complicate efforts to control the disease, according to The Lancet.