Pandemrix

Pandemrix, marketed as "Prepandrix", is a pre-pandemic influenza vaccine for the H5N1 virus, or Bird flu. The vaccine contains an Immunologic adjuvant and an inactivated flu virus from a strain of the H5N1 virus found in Vietnam in 2004 ("A/Vietnam/1194/2004"). A pre-pandemic vaccine is intended for use in the early stages of a pandemic before a "pandemic vaccine" can be developed specifically for that outbreak.

The vaccine is the H5N1 vaccine approved for use by the European Commission on 20^th May 2008 upon the recommendations of The European Medicines Agency (EMEA). [ [http://www.emea.europa.eu/humandocs/Humans/EPAR/pandemrix/pandemrix.htm EMEA Pandemrix page] ] The vaccine is only approved for use when a H5N1 Influenza pandemic has been officially declared by the WHO or EU, since the vaccine only offers significant inoculation for up to 6 months. [ [http://www.emea.europa.eu/humandocs/PDFs/EPAR/pandemrix/H-832-en1.pdf European Public Assessment Report (summary for the public)] ]

Advantages over existing pre-pandemic vaccines

Whilst other H5N1 vaccines have been developed (see H5N1 clinical trials), the use of a proprietary adjuvant boosts the potency of the body’s immune response, meaning that much less of the inactivated virus is needed (2 x 3.8 µg instead of 2 x 90 µg (Open access) Leroux-Roels et. al, "PLoS One", Volume 3, Issue 2, e1665, February 2008 [http://www.plosone.org/article/info:doi%2F10.1371%2Fjournal.pone.0001665] DOI|10.1371/journal.pone.0001665] ). This is particularly useful, since once a pandemic is declared and pandemic vaccines are prepared, the inactivated virus will be at a premium.

The vaccine showed protective antibodies for the H5N1 "A/Vietnam/1194/2004" strain (recommended for study by the WHO) in 84% of people receiving the vaccine, considerably above the 70% minimum. [ [http://www.emea.europa.eu/humandocs/PDFs/EPAR/pandemrix/H-832-en1.pdf EMEA report] ] Furthermore, other studies show the vaccine to offer good "cross protection" against three other H5N1 strains (clades); offering protection against "A/Indonesia/5/2005" (claude 2.1), [Leroux-Roels et al. "Lancet", Vol. 370, No. 9587. (18 August 2007), pp. 580-589. [http://linkinghub.elsevier.com/retrieve/pii/S0140673607612975 article] ] "A/Anhui/1/2005" (clade 2.2) and "A/turkey/Turkey/1/2005" (clade 2.3). These are the clades recommended for study by the WHO ("A/Vietnam/1194/2004" is clade 1).

Dosage

The vaccine is supplied in separate vials one containing the adjuvant and the other the inactivated virus, [ [http://www.emea.europa.eu/humandocs/PDFs/EPAR/pandemrix/H-832-en2.pdf Packaging information] ] which require mixing before intramuscular injection. For full efficacy, two doses of the vaccine must be given 21 days apart, although immune response is observed in some cases after the first dose (see references below).

Media Coverage

The vaccine was developed by GSK and is marketed under the trademark "Prepandrix". [ [http://www.gsk.com/media/pressreleases/2008/2008_pressrelease_10048.htm GSK press-release ("Not for distribution to US Media")] ] In the same press release GSK announced that they had signed contracts with the US and several European countries, and had sold £146 million of its pre-pandemic vaccine and bulk antigen, and reaffirmed that they would donate 50 million doses to the WHO over three years (amounting to 25 million vaccinations since two doses are required per person).

The vaccine has received positive coverage in the business sections of the mainstream UK press; the Guardian, [the Guardian, May 19 2008, Financial section p24, [http://www.guardian.co.uk/business/2008/may/19/glaxosmithklinebusiness.pharmaceuticals article] ] the Financial Times, [The FT In depth, May 20^th 2008 [http://www.ft.com/cms/s/0/f2b69bec-25d8-11dd-b510-000077b07658.html?nclick_check=1 article] ] The Economist, [Science & Technology, "A shot in the dark no more", May 22^nd 2008 [http://www.economist.com/science/displaystory.cfm?story_id=11402747 article] ] and BBC online [ "Glaxo to market bird flu vaccine" Monday, 19^th May 2008 [http://news.bbc.co.uk/1/hi/business/7407714.stm article] ] Little coverage was seen in the US media [Only one article found in US media, from The Wall Street Journal [http://online.wsj.com/article/SB121115520068602285.html article] ] presumably since approval was for the EU only, and the GSK press release was headed "Not for distribution to US Media".

ee also

* Avian influenza
* H5N1
* H5N1 clinical trials
* Influenza
* Oseltamivir & Zanamivir - antiviral drugs used in the treatment and prophylaxis of influenza

References