Last week, Australia and the USA announced that they would begin trials of an H1N1 vaccine. Vaccination against H1N1 will be an important development in controlling the impact of the pandemic. However, several thorny issues exist around vaccine manufacture and approval.All countries will require the vaccine but current global manufacturing capacity will not be able to meet this demand. Additionally, experts think that individuals might need two doses of the vaccine instead of one, reducing capacity further. Vaccine manufacturers are also struggling to produce good vaccine yields with the H1N1 seed virus.One way to ease these supply problems is the use of adjuvants in a vaccine. On July 7, WHO’s Strategic Advisory Group of Experts on Immunization recommended that vaccine formulated with oil-in-water adjuvants and live-attenuated influenza vaccines should be promoted to help increase the global supply of a vaccine and because they are better at protecting against strain variations. Yet there are signs that the USA might not follow this recommendation.
“Adjuvant use would be contingent upon showing that it was needed or clearly beneficial”, Jesse Goodman, acting chief scientist and deputy commissioner of the Food and Drug Administration told a press briefing on July 17. The USA must support the use of dose-sparing strategies to avoid depletion of an already short vaccine supply. [“Dosage-sparing strategies” means use of Novartis’ and Glaxo’s adjuvants to reduce the amount of antigen needed, since otherwise the US will not have enough antigen for its population until several months after school starts. I infer that the Lancet means if the US wants to vaccinate everyone in a hurry, it has no choice but to use these adjuvants.–Nass]As well as availability, safety of an H1N1 vaccine is a concern. Many national regulatory agencies have set-up fast-track approval processes for the H1N1 vaccine, which means that a vaccine might be licensed without the usual safety and efficacy data requirements. Vaccine safety will therefore have to be monitored through post-marketing surveillance. But some fear a repeat of the 1976 H1N1 outbreak in the USA, where mass vaccination was associated with complications, which stopped the campaign and led to the withdrawal of the vaccine.Countries need to assess carefully the risks and benefits of rapid approval of an H1N1 vaccine, especially since the disease has so far been mild with most patients making a full recovery. They must also ensure that they have strong post-marketing surveillance in place before rolling out a vaccine.
From the Aug 1, 2009 Lancet online: