The March 2013 issue of Discover Magazine provides a chilling overview of why a standard vaccine against pertussis (whooping cough) is no longer as effective as we hoped. About 20 years ago the US switched from killed whole bacteria vaccine to one that contained five key proteins. The change was necessitated by some severe reactions to the original vaccine. http://discovermagazine.com/2013/march#.URdn-2fn_1k
[PVirot, WHO Ethiopia 2002.]
It has come to light that the effects of the current pertussis vaccine, given in combination with tetanus and diphtheria immunization (DPT) last only a short time, as little as one year for adults receiving the booster. It seems that the five chosen bacteria proteins may have evolved and that those in the vaccine confer less immunity.
There are efforts to find new adjuvants to enhance efficacy, but what we are witnessing is a constant battle for balance between finding both safe and effective health interventions. http://www.ncbi.nlm.nih.gov/pubmed/23291942
Why should malaria program people be concerned about pertussis? Recent trials of the new RTS,S/AS02D malaria vaccine is that research trials of this new malaria tool were designed to integrate it into existing childhood immunization programs, including DPT. Not only are we concerned about whether the malaria vaccine works, but whether there might be any negative interactions with other concurrent vaccines. http://www.ncbi.nlm.nih.gov/pubmed/23297680
Community members may not easily distinguish all the different diseases in a vaccination program, but the success or failure of any one component may affect their attitudes to the whole package.
In the case of malaria, an effective vaccine that guarantees more protection than those currently under trial, will be important tools in efforts to control the disease. Vaccines may not yet provide the key to elimination. Also as we can see, vaccines that were once effective may loose their edge, much as parasites and vectors may develop resistance to medicines and insecticides. That is why program managers must always ensure adequate resources for a multi-intervention approach.