How it began
Cuban researchers led by Vicente Verez-Bencomo developed a conjugate vaccine against Haemophilus influenzae type b (Hib) that used, for the first time, a synthetic carbohydrate antigen. A patent application by Verez and Roy on oligosaccharides derived from ribose-ribitol-phosphate and vaccines containing them was published by the World Intellectual Property Organization in 2001. The team reported the vaccine in the journal Science in 2004. It was evaluated in clinical trials in Cuba.
Before it existed
Existing Hib vaccines were of natural origin: their sugar antigen was obtained from the bacterium. World Health Organization guidance on the production and control of Hib vaccines was written for those natural products. Because no guideline covered a vaccine made by chemical synthesis, Cuban regulators had to build their own approval strategy, adapting 11 of the 15 WHO recommendations and writing four new requirements with a similar rationale.
How it works
Hib is surrounded by a sugar coat. In Quimi-Hib a fragment of that sugar is built by chemical synthesis and then joined, or conjugated, to a carrier protein, which is what makes it a conjugate vaccine. The Academy of Sciences for the developing world, TWAS, records this as the first use of a synthetic carbohydrate antigen in such a vaccine. In the trials in Cuba the vaccine produced long-term protective antibody levels that compared well with licensed products made from the natural bacterial sugar.
Where it stands today
The vaccine was introduced into the National Immunization Program of Cuba in 2004. By the early 2020s more than 40 million doses had been given, according to an interview in MEDICC Review. A study of its regulation describes Quimi-Hib as a Cuban vaccine obtained by chemical synthesis and unique in the world, and as the first approved vaccine of this type.
