By Richard Black
BBC science correspondent
Cuban scientists have given details of a new vaccine against a bacterium which causes meningitis and pneumonia.
Cuba plans to give the vaccine to all under-five-year-olds
It is made using a novel synthetic technology, and the scientists hope it will be cheaper than existing vaccines against Haemophilus influenzae or Hib.
But doubts remain over how effective it is and how much it will cost.
Hib is certainly an important bug - the World Health Organisation estimates it kills between 5-700,000 children each year from pneumonia and meningitis.
No price given
The key ingredient of any vaccine is the antigen, the bit which our immune system learns to recognise and fight.
In every other successful vaccine the antigen comes from the real bacterium or virus.
But this Cuban vaccine is different - the antigen is synthetic.
The advantage potentially is cost.
Existing Hib vaccines cost around $3 per shot; Cuban scientists say their synthetic vaccine will be cheaper but have not given a firm price.
So convinced is the Cuban Government of its effectiveness that they are planning to give the new vaccine to every child under five next year.
But so far they have not released data proving that it works as well as currently available Hib vaccines.
Together with the Gates Foundation and companies in India, the WHO is working on ways to bring the price of existing vaccines down to around 40 cents per shot.
Cuban manufacturers would be doing well to meet that price, however clever the technology.