Bill Gates claims that criticising pharmaceutical companies for charging high prices for vaccines will deter them from developing the medicines needed to fight diseases in poor countries (Report, 26 January). Let us keep in mind the $19bn made by the two companies – UK-based GSK and Pfizer – solely on sales of a vaccine that protects children against pneumonia, a condition that kills 1 million children every year.

Mr Gates wrongly claims that MSF has called for vaccines to be available for free. We have in fact called on GSK and Pfizer to reduce the price to $5 per child. This is half of the current cost, which we are worried is unaffordable for many countries. An Indian manufacturer has already indicated that it could make the vaccine for $6, so we believe our call is perfectly reasonable.

Mr Gates also says that MSF doesn’t “actually know anything about the costs” of the vaccine’s production. The pharmaceutical industry shrouds its vaccine production costs in secrecy, despite our repeated calls for them to open the books. MSF has asked the Gates Foundation for its more detailed cost information on the pneumonia vaccine for years, to no avail; we urge the Gates Foundation to publicly share this information.

Kate Elder

Vaccines policy adviser at MSF Access Campaign

• The creation of children using DNA from three parents in order to prevent genetic defects (Nobel laureates join scientists worldwide to urge MPs to permit ‘three-parent’ IVF, 31 January) is described by some as “playing God”. This is wrong. If you believe in such a being, the process would be better described as “correcting God”.

John Illingworth

Bradford, West Yorkshire