In countries where women with HIV have limited access to safe alternatives to breastfeeding, it may be both possible and desirable to evaluate HIV preventive vaccines as a means of protecting breastfed children from HIV.

One model for this is the strategy used to prevent transmission of hepatitis B from HBV-positive mothers to their babies, which involves dual vaccination of newborn babies with immunoglobulin (i.e. antibodies) and an active vaccine, followed by booster injections later.

The establishment of medical infrastructure to deliver short-course antiretroviral treatments to prevent HIV transmission from mothers to babies would also permit the evaluation of such vaccines. Breastfed babies are at relatively high risk of HIV, and at a more predictable risk than other populations that might be included in trials, so trials could give clear answers with relatively small numbers of children taking part. Since babies, including those born to HIV positive women, are routinely vaccinated against a number of diseases in most countries, any successful vaccine could be rapidly deployed.

One obstacle to this use of a vaccine is biological, in that newborn infants do not respond in the same way as older children to vaccines.  Another obstacle is commercial, since this use of a vaccine would have no market in wealthier countries where women have safe access to breast milk substitutes. However, as vaccine developers move away from the ‘trickle down’ model of product development, towards the goal of developing products to meet global needs as effectively as possible, so such arguments diminish in force.

By the year 2000 Phase I trials on recombinant canarypox vaccines had been completed in the USA and trials of different vaccine candidates had been under discussion in Uganda, Haiti and South Africa. If any vaccine were to prove successful in protecting young children it would immediately become a priority to evaluate it for the protection of adults, although the framework in which such trials would be conducted is generally quite separate.