New vaccine for Dengue is coming .. shortly “Butantan - DV”

 New vaccine for Dengue is coming .. shortly     “Butantan - DV”

Interim results of a live attenuated single dose Dengue vaccine is highly promising. Phase III trials ongoing in Brazil for five years , analysis at the end of 2 years are published in NEJM this month .

🔴Situation of dengue worldwide  & India

Almost 300 Million cases of dengue worldwide.In India Dengue and Leptospirosis constitute major morbidity and mortality even now Mortality was .much high before 2009 Since the awareness ,early detection and WHO treatment guidelines implemented we could bring down the mortality .Even though dengue vaccines were available in other countries so far we are yet to go for it .Main reason , there were safety concerns about the vaccines which were used in some countries. 

 🔴 Vaccines available now for Dengue 

Out of many vaccines in phase III trials two are in the market 

     🧁Dengvaxia ( CYD-TDV) a live attenuated vaccine containing all the four strains (I,II, III,IV) of the virus . It is licensed for ages 9 - 45 years. With 3 doses spaced over one year. When it was used in some countries there were cases with high severity and death when infection occurred in vaccinated individuals in cases vaccination was done in people who didn't have previous exposure to the virus .  So at present it is recommended after serological testing to demonstrate previous infection or if this is not possible..in countries where prevalence and chance of exposure is high.Efficacy for protection also varies between strains. Not highly efficacious .

    🧁TAK -003 also called as Qdenga (Takeda) a better vaccine where two dose closely spaced . Age recommended is 6 to 45 years in Indonesia and  4 years to 60  years in Brazil. One more advantage of this vaccine is it is safe irrespective of the previous serostatus 

 🔴So what is the need for a new vaccine 

🍄A vaccine which can be used in wider age group , (susceptibility of mortality )

🍄Lesser number of doses , or closer interval ,assuring early protection. Faster protection will help travelers to have immunity in short period before visiting a highly endemic country eg Asia and South American region

🍄 Can be  given irrespective of serostatus , without fear of antibody dependent enhanced severity and complications 

 🔴 About the study of the new Live vaccine Butantan-DV

Study was conducted in Brazil 16235 participants 10239 got a single dose of vaccine and 5976 got placebo. After successful completion and favorable efficacy and safety profile during phase I and Phase II trials Complete study duration as per plan is five years. 

Vaccines were studied in three age groups. 2-6 year, 7-17 and 18-59 years 

Overall efficacy was assessed by the number of symptomatic virologically (PCR) proved cases of dengue happening after 28 days of vaccination.

Adverse events following immunization were also assessed in both arms

Interim results after 2 year analysis

🍄Overall efficacy was 79.6 ( A little lower among seronegative group  73.6  and better 83.7 in seropositive group .

🍄Vaccine efficacy was 80.1 percent in the age group of 2-6,      77.8 percent in the 7-17 age group and 90 percent in 18-59 age group 

Safety profile 

Even though adverse events were higher in the vaccination arm ( 58.3 versus 45.8), there were no major adverse events

 🔴What are the limitations. Can we adopt it now ?

The protection against strains III and IV were not possible as cases with this strains were less. Severity and incidence are more common with Strain II and I 

There is need for longer follow up for the safety profile as we had bad experience earlier