The government is carrying out a feasibility study into importing vaccine against the dengue virus as the viral disease has spread almost across the country and may turn into an epidemic.
“The government is doing everything that is necessary to control the dengue virus. We’re talking with the dengue vaccine manufacturing company and carrying out a feasibility study on dengue vaccine in our country,” Professor Dr Abul Kalam Azad, director-general of the Directorate General of Health Services (DGHS), told daily sun on Monday.
He said they held a meeting with a delegation led by a director of Sanofi, a dengue vaccine manufacturing company, on Sunday and asked for details about dengue vaccine.
“But they couldn’t give us detailed information about it. We have sought information in detail within a week. Then our immunization committee will examine the feasibility of the dengue vaccine. If everything remains OK, then it will take around three to four months to import the vaccine,” he added.
Mentioning that a dengue vaccine may cost Tk 5,000-6,000, Azad also said the vaccine is not feasible actually in Bangladesh as it may be used only for the dengue patients who are infected for a second time.
“Otherwise if the dengue vaccine is used for first-time dengue patients, it may create reaction inside their bodies.”
Talking to the daily sun, Dr. ASM Alamgir, principal scientific officer of the Institute of Epidemiology, Disease Control and Research (IEDCR), said, “The dengue vaccine can only be used for the patients diagnosed with dengue for the second time. Before using it, patients’ condition will have to be detected whether they were earlier dengue positive or not.”
According to the World Health Organization (WHO), one dengue vaccine has been licensed, Dengvaxia® (CYD-TDV), developed by Sanofi Pasteur.
“It was first licensed for use for individuals of 9-45 years’ old living in endemic areas and is now licensed in 20 countries. CYD-TDV is a live recombinant tetravalent dengue vaccine (CYD-TDV), given as a three-dose series on a 0/6/12 month schedule.”
“The first licensed dengue vaccine, CYD-TDV (Dengvaxia®), is a live attenuated, recombinant tetravalent vaccine employing the attenuated YF virus 17D vaccine strain as the replication backbone.
The vaccination schedule consists of three injections of 0.5mL, given subcutaneously, administered at six-month intervals,” it added.
Explaining its position about the dengue vaccine, the WHO said the CYD-TDV has been shown in clinical trials to be efficacious and safe in persons who have had a dengue virus infection in the past (seropositive individuals), but increases the risk of severe dengue in those who experience their first natural dengue infection after vaccination (seronegative individuals).
“Therefore, countries should consider the introduction of the dengue vaccine CYD-TDV only if the vaccination of seronegative individuals can be avoided.
For countries considering vaccination as part of their dengue control programme, prevaccination screening for past dengue infection is the recommended strategy,” it said.
The WHO report further said with this strategy, only persons with evidence of a past dengue infection would be vaccinated (based on an antibody test, or on a documented laboratory-confirmed dengue infection in the past).
“Only if pre-vaccination screening is not feasible, vaccination without individual screening could be considered in carefully selected areas with recent documentation of seroprevalence rates of at least 80 per cent by the age of 9 years,” it added.
The world health body said as vaccine-induced protection against dengue in seropositive individuals is high, but not complete, the breakthrough disease will occur in some seropositive vaccinees. These limitations will need to be communicated to populations offered vaccination.
“The organisation further said decisions about implementing a pre-vaccination screening strategy will require a careful assessment at the country level, including consideration of the sensitivity and specificity of available tests and of local priorities, dengue epidemiology, country-specific dengue hospitalization rates, and affordability of both CYD-TDV and screening tests. Vaccination should be considered as part of an integrated dengue prevention and control strategy,” it said.
According to reports, in 2019 the US Food and Drug Administration announced approved Dengvaxia, for the prevention of dengue disease caused by all dengue virus serotypes (1, 2, 3 and 4) in people ages 9 through 16 who have laboratory-confirmed previous dengue infection and who live in endemic areas.
According to a report published in the Sanofi Pasteur, licensed for producing the dengue vaccine, the European Commission has granted marketing authorization for Dengvaxia®, dengue vaccine in 2018.
According to the WHO, dengue is a mosquito-borne viral disease and the dengue virus is transmitted by female mosquitoes mainly of the species Aedes aegypti and, to a lesser extent, Ae. albopictus.
Dengue is caused by a virus of the Flaviviridae family and there are four distinct, but closely related, serotypes of the virus that cause dengue (DEN-1, DEN-2, DEN-3 and DEN-4).
Recovery from infection by one provides lifelong immunity against that particular serotype. However, cross-immunity to the other serotypes after recovery is only partial and temporary. Subsequent infections (secondary infection) by other serotypes increase the risk of developing severe dengue, it added.