Vaccination is considered the cornerstone of influenza control in humans. Vaccination against seasonal influenza has been in use for more than 50 years, has an excellent safety record and provides a high degree of protection. It is currently recommended in most countries for use in risk groups (mainly the elderly and people with an underlying medical condition), but routine use in children (1) and even universal immunisation programmes exist or are under consideration in some countries/regions.
Yet, many challenges remain that are further amplified when it comes to the challenge of pandemic vaccines. Longer-acting vaccines that are more broadly cross-protective against heterologous strains and clades of influenza are required, immune responses in elderly and small children need to be optimised, and cell-culture production (which could be scaled up much faster in the case of a pandemic) is about to replace egg-based production facilities (where egg supply might be particularly vulnerable during a pandemic derived from an avian strain of influenza).
The use of vaccination in poultry is complex and only a limited number of countries have implemented a vaccination strategy to date. With currently available vaccines, avian influenza (AI) viruses can still infect and replicate in vaccinated birds. However, they protect against clinical signs and mortality, reduce the level and duration of virus shedding and hence decrease possibilities of transmission. There is evidence that when used adequately and as part of a wider control strategy in combination with other measures, such as increased biosecurity, stamping out and appropriate surveillance, vaccination may be a powerful tool in the control and eradication of AI. A key issue for the use of vaccines is the ability to detect birds exposed to the field virus in a vaccinated population. This is known as the DIVA strategy (differentiating infected from vaccinated animals). The development of new DIVA vaccines with a wider cross-protection and species range that can be administered on a large scale and at low cost is thus an important research task.
Some of the earliest funded projects in this catalogue are vaccine projects that have delivered a number of important results: MUCADJ has developed a potent new adjuvant for mucosal (i.e. intranasal) delivery of human influenza vaccines and an H7N1 vaccine developed by the FLUPAN consortium is currently in clinical trials. A novel computer algorithm that assesses the relatedness of influenza viruses was developed by NOVAFLU, and has already been integrated into the biannual WHO (World Health Organisation) vaccine strain selection process. FLUAID works on vaccine candidate strains as well as on diagnostic tests with partners in Asia, Australia and Africa. A remarkably high number of consortia (eight) are led by industry, in particular small and medium-sized enterprises (SMEs). These are MUCADJ, CHIMERIC VACCINES, UNIVERSAL VACCINE, SARS/FLU VACCINE, FLUVACC, AIV VACC DIAGNOSIS, Intranasal H5vaccine and FluVac. The last two, as well as PANFLUVAC, are the result of the most recent (and last FP6) call for proposals. They have just started, and address the special challenges of the clinical development of a pandemic human vaccine through novel adjuvants, delivery methods and genetically engineered vaccine viruses. Similarly, AIV VACC DIAGNOSIS and NOVADUCK, funded through the same recent call, are both aimed at creating effective live influenza vaccines for poultry that allow the distinction of vaccinated and infected animals through specific markers and could be mass administered. Importantly, the Public Health project FLUSECURE is dedicated to establishing a network of public health institutes as a partner for the vaccine industry to promote the production of an effective pandemic vaccine.
- European Centre for Disease Protection and Control (ECDC): Technical Report of the Scientific Panel on Vaccines and Immunisation: Infant and children seasonal immunisation against influenza on a routine basis during inter-pandemic period, Stockholm, January 2007 (http://www.ecdc.eu.int/documents/pdf/ Flu_vacc_18_Jan.pdf)