Pandemrix

Pandemrix

Vaccine description
Target disease	Pandemic H1N1/09 virus
Type	Killed/Inactivated
Clinical data
Licence data	EMA:Link
Pregnancy cat.	?
Legal status	P (UK)
Routes	Intramuscular injection
Identifiers
ATC code	J07BB02
N (what is this?)  (verify)

Influenza (Flu)
Types
Avian (A/H5N1 subtype) Canine Equine Swine (A/H1N1 subtype)
Vaccines
2009 pandemic (Pandemrix) ACAM-FLU-A Fluzone Influvac Live attenuated (FluMist) Optaflu
Treatment
Amantadine Arbidol Laninamivir Oseltamivir Peramivir Rimantadine Vitamin D Zanamivir
Pandemics
2009 Swine 1968–1969 Hong Kong 1918
Outbreaks
2008 West Bengal 2007 Bernard Matthews H5N1 2007 Australian equine 2006 H5N1 India 1976 swine flu
See also
Flu season Influenza evolution Influenza research Influenza-like illness
v t e

Pandemrix is an influenza vaccine for influenza pandemics, such as the H1N1 2009 flu pandemic colloquially called the swine flu. The vaccine was developed by GlaxoSmithKline^[1] and patented in September 2006.^[2]

The vaccine is one of the H1N1 vaccines approved for use by the European Commission in September 2009 upon the recommendations of the European Medicines Agency (EMEA).^[3] The vaccine is only approved for use when an H1N1 influenza pandemic has been officially declared by the World Health Organization (WHO) or European Union (EU).^[3] This vaccine was initially developed as a pandemic mock-up vaccine using an H5N1 strain.^[4]

The Swedish Medical Products Agency (MPA) and The Finnish National Institute for Health and Welfare (THL) have began in Aug 2010 investigations about narcolepsy as possible side effect to Pandemrix flu vaccination in children,^[5] and found at least 6.6 times increased risk among children and youths, or at least 3.6 additional cases of narcolepsy per 100.000 vaccinated subject.^[6]

Constituents

As well as a the active antigen derived from A/California/7/2009 (H1N1), the vaccine contains an immunologic adjuvant AS03 which consists of DL-α-tocopherol (vitamin E), squalene and polysorbate 80.

Thiomersal (thimerosal) is added as a preservative. Being manufactured in chicken eggs, it contains trace amounts of egg proteins. Additional important non-medicinal ingredients are formaldehyde, sodium deoxycholate, and sucrose.^[7]

Use of adjuvant

While other 2009 H1N1 vaccines have been developed, the use of a proprietary immunologic adjuvant is claimed to boost the potency of the body’s immune response, meaning that only a quarter of the inactivated virus is needed. ^[7]

Professor David Salisbury, Head of Immunisation at the UK Department of Health said the vaccines with adjuvants offer good protection even if the virus changes over time; "One of the advantages with adjuvanted vaccines is their ability to protect against drifted (mutated) strains. It opens the door for a whole new strategy in dealing with flu."^[8]

Dosage

The vaccine is supplied in separate vials, one containing the adjuvant, and the other the inactivated virus,^[9] which require mixing before intramuscular injection. Originally it was thought that two doses given 21 days apart would be required for full efficacy.^{[citation needed]}. Subsequent testing has allowed the UK programme to consist of just a single dose for most people, with a two-dose schedule for children under the age of 10 years and immunocompromised adults.^[10]

Availability

As of 3 December 2009, 11.2 million doses of Pandemrix have been delivered to health services in the UK, where the vaccine forms the bulk of the governments mass vaccination programme.^[8]

Clinical trials

The EMEA reported results from some clinical trials in the CHMP Assessment Report. These relate to vaccination against H5N1 (Bird Flu) and not H1N1 (Swine Flu)^[11]

H5N1-007 was initiated at a single site in Belgium (Ghent) in March 2006.

H5N1-008 was initiated at 41 sites in seven countries (6 EU MS plus Russia) in May 2006.

H5N1-002 was initiated on 24 March 2007 in four SE Asian countries.

GlaxoSmithKline reported results from the second clinical trial,^[12] from the pediatric clinical trial,^[13] and the response from the elderly population.^[14]

Side effects

GlaxoSmithKline state in their Patient Information Leaflet^[15] that the following may occur.

• Very common (affects more than 1 in 10 people):
  • Headache
  • Tiredness
  • Pain, redness, swelling or a hard lump at the injection site
  • Fever
  • Aching muscles, joint pain

• Common (affects at least 1 in 100):
  • Warmth, itching or bruising at the injection site
  • Increased sweating, shivering, flu-like symptoms
  • Swollen glands in the neck, armpit or groin

• Uncommon (affects at least 1 in 1,000):
  • Tingling or numbness of the hands or feet
  • General constitutional upset of sleepiness or sleeplessness, generally feeling unwell, dizziness.
  • Diarrhea, vomiting, stomach pain, feeling sick
  • Skin reactions of itching, rash or urticaria (hives)

• Rare (affects at least 1 in 10,000):
  • Serious generalised allergic reactions of anaphylaxis
  • Fits
  • Severe stabbing or throbbing pain along one or more nerves
  • Low blood platelet count which can result in bleeding or bruising

• Very Rare (affects less than 1 in 10,000 people):
  • Vasculitis
  • Neurological disorders such as encephalomyelitis, neuritis or Guillain–Barré syndrome temporary paralysis

Media coverage

The vaccine has received coverage in the business sections of the mainstream UK and International press, including by The Press Association,^[16] The British Medical Journal,^[17] The Wall Street Journal,^[18] and also the Daily Telegraph.^[19]

Narcolepsy investigations in the European Union

The Swedish Medical Products Agency (MPA) and The Finnish National Institute for Health and Welfare (THL) have received in summer 2010 reports from Swedish and Finnish health care professionals regarding narcolepsy as suspected adverse drug reaction following Pandemrix flu vaccination. The reports concern children aged 12–16 years where symptoms compatible with narcolepsy, diagnosed after thorough medical investigation, have occurred one to two months after vaccination. Consumer reports describing similar symptoms have also been received. Both organizations have, in consultation with external experts, began to assess the possible relationship between the vaccination and the reported reactions. MPA and THL have been in contact with other EU member states to get information if there are any reports in other countries.

Currently, THL is recommending that further Pandemrix vaccinations are discontinued pending further investigation into 15 cases of recently vaccinated children developing narcolepsy in late 2009 and early 2010.^[20] Most recently, THL raised the figure to 17, while the expected average occurrence would be six cases annually. In Sweden, MPA has discovered 12 confirmed and another 12 suspected cases. Additionally, MPA says it is aware of individual case reports from France, Norway and Germany.^[21]

On August 27, 2010, the European Medicines Agency announced that the agency's Committee for Medicinal Products for Human Use would be launching a review of Pandemrix in light of the "limited number of cases"^[22] reported in Finland and Sweden, so as to "determine whether there is evidence for a causal association" ^[23]

In August 2010 the Swedish MPA issued a statement which included the following: "An investigation is ongoing, but any relationship between the vaccination and the reported symptoms can not be concluded." ^[24]

THL concluded in February 2011 that there is a clear connection between Pandemrix vaccination campaign of 2009 and 2010 and narcolepsy epidemic in Finland. There was a nine times higher probability to get narcolepsy with vaccination than without it. Total of 52 cases of narcolepsy have been found in Finland during 2009–2010 and 90 % of these children had taken Pandemrix vaccination. Authorities believe that the number of cases may still increase.^[25][26]

At the end of March 2011, an MPA press release stated: "Results from a Swedish registry based cohort study indicate a 4-fold increased risk of narcolepsy in children and adolescents below the age of 20 vaccinated with Pandemrix, compared to children of the same age that were not vaccinated." ^[27] The same study found no increased risk in adults who were vaccinated with Pandemrix. While cautioning that the increase in risk for children is still uncertain in magnitude, it recommends they not be vaccinated.

A new study by the Stanford University School of Medicine examined narcolepsy incidence in relation to upper airway infections and a H1N1 vaccine (not Pandemrix) in Chinese patients. Their principal conclusion was that an increased incidence of narcolepsy was seen following a wave of upper airway infections (such as H1N1 influenza). They found no correlation between vaccination and narcolepsy. According to the authors "The new finding of an association with infection, and not vaccination, is important as it suggests that limiting vaccination because of a fear of narcolepsy could actually increase overall risk."^[28] Since narcolepsy is now believed to be an autoimmune disease ^[29] the authors suspect that these upper airway infections trigger an immune response which leads ultimately to narcolepsy in susceptible individuals. Pandemrix contains two adjuvants designed to provoke a stronger immune response. These were not in the vaccine used in China.

See also

• Oseltamivir and Zanamivir – antiviral drugs used in the treatment and prophylaxis of influenza
• Influenza vaccine
• 2009 flu pandemic vaccine

References