Demographically, the coming years are expected to show a reduced demand for paediatric vaccines due to lower birth rates. On the other hand, the increase in life expectancy means that the population over 60 years of age will represent about 40% of the total population in 2040. This evolution

has an important bearing on vaccine needs and production plant capacity. Indeed, using 15 μg of antigen per dose as anticipated for a non-adjuvanted split inactivated vaccine, Butantan would not be able to meet the demand of the Ministry of Health for seasonal influenza vaccine. Butantan’s production plant will operate for 4–6 months per year to produce southern hemisphere influenza vaccine, and would remain idle for a full semester. It could therefore be envisaged to produce the northern hemisphere formulation during PF 01367338 these inactive months, which could be provided to other governments for immunization of their target PI3K Inhibitor Library cell assay groups, in exchange for southern hemisphere vaccine. Approval for this strategy remains to be sought from the technology provider (sanofi pasteur). There are further complexities in the timing and formulation of influenza

vaccine in Brazil. Vaccination in the north and north-east currently takes place as elsewhere in the country in April, yet this is four months after the local seasonal influenza peak. Analysis of an epidemiological survey suggests that vaccination should take place earlier in this region. The exact transmission pathway that determines the origin of the virus is not clearly understood, nor the onset of a significant drop in temperature that sparks influenza incidence. Even if we could use the northern hemisphere formulation in this region, our inability to meet the demand for the southern hemisphere vaccine would not change, as the north and north-eastern regions only needs 2–5 million doses per year. Further,

the difference in protection using one or the other formulation is not well defined [6] as this will depend on the extent to which the viruses have drifted. Butantan considers that the best option to address potential TCL shortages of influenza vaccine is antigen sparing through the use of adjuvants. We first intended to formulate our influenza vaccines using aluminium hydroxide. We anticipated that by doing this we would not only be able to maximize production capacity by reducing the HA antigen content per dose, but also to lower the price of the vaccine to make it accessible for the least developed countries. Unfortunately, results of many published animal and clinical assays, mostly for H5N1, show that immunopotentiation by aluminium hydroxide is at best moderate, and most likely dependent on the source of aluminium salts, although the recent establishment of the mechanism of potentiation of aluminium salts [7] should lead to the improved performance of aluminium preparations.