A description of the process of seasonal and H5N1 influenza vaccine virus selection

[Anne]

A description of the process of seasonal and H5N1 influenza vaccine virus selection and development

Draft
19 November 2007

http://www.who.int/csr/disease/avian_influenza/Fluvaccvirusselection.pdf

 

[Snowy Owl]

Re: A description of the process of seasonal and H5N1 influenza vaccine virus selecti

Re: A description of the process of seasonal and H5N1 influenza vaccine virus selecti

Merci Anne

DRAFT​

​

19 Nov 2007
​

A Description of the Process of Seasonal and H5N1 Influenza

Vaccine Virus Selection and Development
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Introduction
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Influenza vaccine is the best available protection against the disease. Among all vaccines,,however, the process of making influenza vaccines is considered uniquely complicated and difficult.

One reason is that the constantly evolving nature of influenza viruses requires continuous global monitoring and frequent reformulation of the vaccine strains.

Another reason is that the rapid spread of these viruses during seasonal epidemics, as well as the occasional pandemic, means that each step in the vaccine process must be completed within very tight time frames if vaccine is to be manufactured and delivered in time.

In response to the realities imposed by influenza, a highly functional process has evolved over decades in which the public and private sectors work together to develop and produce influenza vaccine.

This paper, and the accompanying Diagram, describe many aspects of the influenza vaccine process including important similarities and differences in how seasonal human influenza viruses and H5N1 viruses are handled.​

Background​

The global monitoring of influenza viruses is essential for identifying influenza threats (risk assessment) and providing the information needed by countries to respond to these threat.

In practice, the global link between risk assessment and risk response activities has long been the Global Influenza Surveillance Network (GISN), which continues to grow and currently includes 121 National Influenza Centres (NICs) in 92 countries and 5 WHO Collaborating Centres (WHOCCs).

Together, this network processes an estimated 150,000 to 200,000 respiratory specimens per year with approximately 5000 viruses voluntarily shared by the NICs undergoing extensive antigenic and genetic characterization among the WHO CCs.

The information provided by GISN through its participating institutions has identified new influenza threats, substantially helped
define the epidemiology of influenza and the molecular evolution of the viruses, and formed the basis for selecting new influenza vaccine strains and for updating diagnostic tests.

Moreover, the international infrastructure of GISN has provided a platform through which the world's best influenza expertise can be brought together quickly and coordinated to help countries and WHO address influenza.

Since 1971, WHO has provided formal recommendations for the composition of seasonal influenza vaccines based on the information provided by the GISN.

In 1998, the WHO recommendations were increased in frequency from once to twice per year so that separate recommendations could be made and timed appropriately for the northern and southern hemisphere influenza seasons.

Since the development and production of influenza vaccines requires several months, these recommendations precede the period of anticipated use by up to eight months.

Some of the roles of GISN in this regard is to enable the pooling of worldwide information on influenza viruses and to provide the infrastructure for experts to examine all relevant antigenic, virological and immunological data. The results of that data examination in turn allow these experts to select candidate vaccine viruses that might be included -- if they pass additional testing -- in the following season's vaccines.

While the process is difficult, complex
and highly resource demanding, it remains manageable because countries and other entities have worked together collaboratively.

Before 2004, GISN primarily focused on seasonal influenza viruses for vaccine development but since 2004, has expanded its scope to include H5N1 viruses because this virus constitutes an unusually serious pandemic risk.

Therefore, WHO now reviews the available antigenic and genetic data on animal and human H5N1 viruses in addition to the analyses of seasonal vaccine stains and has developed and made H5N1 candidate vaccine viruses available to vaccine producers so they can work on developing safe and effective human H5N1 vaccines for potential productioni.

Some of these H5N1 candidate vaccine viruses have been used by manufacturers to produce human influenza H5N1 vaccines, some of which have been tested in clinical trials.

The entire process of influenza vaccine virus selection and development is possible and successful because it represents a true collaborative effort, involving all members in GISN as well as several other entities including three national regulatory laboratories in the Australian Therapeutics Goods Administration (TGA), the United Kingdom's National Institute of Biological Standards and Control, (NIBSC), and the United States' Food and Drug Administration (FDA), which provide essential input and services to the process, some contract laboratories that do highly specialized parts of the process for seasonal vaccines (but not H5N1 vaccines) and vaccine manufacturers.

The time constraints under which all these parties operate are great because of the epidemiology of influenza and steps that must be completed for vaccine production to take place.

Once influenza viruses appear, either as seasonal outbreaks or, in the case of certain viruses possibly as a new pandemic, the spread of disease can be very quick.

Given this reality, even short delays anywhere in the process can result in significant down stream delays in the availability of influenza vaccines.​

Recent Development​

In June 2007, a revised set of International Health Regulations (IHR) entered into force.

The IHR creates a global, collective system to enable WHO to
1) identify public health threats;
2)assess their risk; and
3) put in place effective public health responses to mitigate their impact.

By accepting to be bound by the IHR, Member States accept to participate and cooperate in this global system.

The IHR is disease specific for only 4 diseases. One of them is human influenza caused by a novel virus (i.e., a virus that has the potential to cause a pandemic).

As such, any case of human influenza by a virus such as H5N1, must be reported to WHO under the IHR.

Each notification must then be followed up with sufficiently detailed information to allow WHO to thoroughly assess whether the new case signals the start of a pandemic.

Under the IHR, WHO is responsible not only for the assessment of risk but also, importantly, to put in place a public health response.

When it comes to influenza, a critical response is the development, production, availability and access to influenza vaccines.

The rapidity with which vaccines can be developed​

will depend on access to the actual virus.

more at the above link Anne First Post

 

[Snowy Owl]

Re: A description of the process of seasonal and H5N1 influenza vaccine virus selecti

Re: A description of the process of seasonal and H5N1 influenza vaccine virus selecti

From the above link

Total Approximate Time to Produce an H5N1 Human Vaccine
Steps 2-5 and 6b-9b :​

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28 - 52 weeks​

i​

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http://www.who.int/csr/disease/avian_influenza/guidelinestopics/en/index5.html​

ii​

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http://www.who.int/csr/disease/influenza/vaccinerecommendations/en/index.html​

iii http://www.who.int/biologicals/publications/ECBS%202005%20Annex%205%20Influenza.pdf