From a public health point of view, vaccinating men as well as women decreases the virus pool within the population, but is only cost-effective if the uptake in the female population is extremely low.[20] In the United States, the cost per quality-adjusted life year is greater than $100,000 for vaccinating the male population, compared to the less than $50,000 for vaccinating the female population.[20] This assumes a 75% vaccination rate. In early 2013 the two companies who sell the most common vaccines announced a price cut to less than $5 per dose to poor countries, as opposed to $130 per dose in the US.[21]