Issued: London UK
Vaccine efficacy was highest against moderate-to-severe influenza, where the disease is associated with the greatest medical and socioeconomic burden. The study met its two primary endpoints, demonstrating 63.2% (97.5% CI: 51.8–72.3) vaccine efficacy against laboratory-confirmed moderate-to-severe influenza, and 49.8% (97.5% CI: 41.8–56.8) vaccine efficacy against influenza of any severity in children six to 35 months of age.
Data from the secondary endpoint, looking at culture-confirmed influenza due to influenza strains matching the vaccine strains, showed vaccine efficacy in this subset was even higher. Vaccine efficacy against moderate-to-severe influenza was 77.6% (97.5% CI: 64.3–86.6) and vaccine efficacy against influenza of any severity was 60.1% (97.5% CI: 49.1–69.0).
“Young children belong to one of the high-risk groups for influenza and are at particular risk of complications and severe disease, even when they are otherwise healthy. In addition, children play a major role in the dissemination of influenza in any community across the world”, said Thomas Breuer, Chief Medical Officer, GSK Vaccines. “This study is the first randomised clinical trial designed to evaluate vaccine efficacy for a Quadrivalent influenza vaccine in young children. It adds to the growing body of evidence to support universal vaccination including all children from six months of age to help prevent influenza in this age group, as well as the spread of influenza across the community.”
The study also found that IIV4 reduced the impact of influenza on healthcare utilisation and daily activities, approximately halving the likelihood of visits to a doctor, antibiotic use, parental work absence and missed day-care related to the current influenza illness. This is the first study to demonstrate the impact, in a randomised clinical trial, of influenza vaccination on the use of antibiotics.
A link to a video related to the publication can be found here: http://www.thelancet.com/lanchi/video
About the study
The study was a Phase III, observer-blind, multinational clinical trial to evaluate the efficacy of IIV4 in the prevention of laboratory-confirmed influenza in children six to 35 months of age.
The study was conducted in five independent cohorts between October 2011 and December 2014, and enrolled 12,018 subjects in 13 countries from Europe, Central America and Asia during the 2011-2012 and 2012-2013 Northern Hemisphere influenza seasons, and from 2012 to 2014 during influenza seasons in subtropical countries to provide robust data on vaccine efficacy.
The two primary endpoints were vaccine efficacy against moderate-to-severe influenza or all influenza (regardless of disease severity) confirmed by reverse transcription polymerase chain reaction (RT-PCR) on nasal swabs.
The safety profile of the IIV4 was comparable with that of the non-influenza control vaccine.
About seasonal influenza
Influenza is an acute, highly contagious, respiratory disease caused by influenza viruses, mainly spread through respiratory droplets. The illness is accompanied by fever and variable degrees of other systemic symptoms, ranging from mild fatigue to respiratory failure and death.
Yearly outbreaks of influenza affect all age groups, but the greatest risk of severe disease or complications when infected are children under 59 months, adults aged 65 years and older, and individuals with immunosuppressive conditions (e.g., HIV/AIDS, receiving chemotherapy or steroids, or malignancy) and pregnant women.[i] The World Health Organization recognizes that children under five years of age, and particularly those under two years of age are a priority group to receive annual influenza vaccination.[ii]
The World Health Organization (WHO) estimates that annual epidemics can be responsible for three to five million cases of severe illness and up to 650,000 deaths per year worldwide.1 The timing, severity, and length of the season varies from one year to another. The flu vaccine is made annually to protect against the flu viruses that research and surveillance indicate will likely be most common during the upcoming flu season.
The severity of the 2017/18 flu season has led to high numbers of hospitalizations and deaths. While vaccine effectiveness varies considerably by season, the flu vaccine is considered the best tool to help protect against influenza disease.
A quadrivalent inactivated vaccine (QIV) offers protection against two influenza A strains and two influenza B strains, therefore considerably reducing chances of mismatch between the vaccine strains and the circulating strains. The World Health Organization has recently highlighted that for the 2017/18 season, QIVs can be expected to provide wider protection against influenza B virus infections than trivalent inactivated vaccines (TIVs) which only contain one B strain instead of two.1
Further information about seasonal influenza can be found at: http://www.who.int/mediacentre/factsheets/fs211/en/
About Fluarix Tetra
Fluarix Tetra was first approved in 2013 in the following European countries: Germany, France and UK, for the prevention of influenza disease in people three years of age and older. It is also currently approved in more than 30 other countries worldwide, and more than 100 million doses have been distributed since launch.
Fluarix Tetra is now indicated for active immunisation of adults and children from six months of age for the prevention of influenza disease caused by the two influenza A virus subtypes and the two influenza B virus types contained in the vaccine, in several countries, including EU and US.
The use of Fluarix Tetra should be based on official recommendations.
Annual revaccination with Fluarix Tetra is recommended because immunity declines during the year after vaccination, and because circulating strains of influenza virus might change from year to year.
Important Safety Information
- Fluarix Tetra is administered by intramuscular injection. If given at the same time as another injectable vaccine, the vaccines should be given at different injection sites.
- Always have a discussion with your healthcare provider about the benefits and risks of being vaccinated with Fluarix Tetra.
- Fluarix Tetra should not be administered to subjects with known hypersensitivity after previous administration of influenza vaccines (including Fluarix Tetra) or to any component of the vaccine. Vaccination with Fluarix Tetra should be postponed in subjects suffering from an acute illness with moderate to high fever. The presence of a minor infection, such as a cold, should not result in the deferral of vaccination.
- Adequate protection against influenza disease may not occur in all persons vaccinated with Fluarix Tetra.
- In clinical trials the common adverse events observed with Fluarix Tetra were:
- In adults (≥18 years): injection site reactions (pain, redness and swelling), muscle aches, headache, fatigue, arthralgia, gastro-intestinal symptoms, shivering and fever.
- In children (3-17 years): injection site reactions (pain, redness & swelling), muscle aches, irritability, fatigue, headache, drowsiness, loss of appetite, arthralgia, gastro-intestinal symptoms, shivering and fever.
- In children (6-35 months): injection site reaction (pain and redness), irritability, loss of appetite, and drowsiness.
See Adverse Reactions section of the Prescribing Information for Fluarix Tetra for other potential adverse reactions and events.
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[i] World Health Organization. WHO influenza (seasonal) factsheet, December 2017. Taken from: http://www.who.int/mediacentre/factsheets/fs211/en/. Last accessed March 2018.
[ii] World Health Organization. Background Paper on Influenza Vaccines and Immunization SAGE Working Group. Taken from: http://www.who.int/immunization/sage/meetings/2012/april/1_Background_Paper_Mar26_v13_cleaned.pdf. Last accessed: March 2018