Update on Influenza Vaccination for the 2005-2006 Season

Canada Communicable Disease Report
Volume 31 • ACS-10
1 November 2005

An Advisory Committee Statement (ACS)
National Advisory Committee on Immnization (NACI)^*

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4 Pages - 204 KB

Preamble

The National Advisory Committee on Immunization (NACI) provides the Public Health Agency of Canada with ongoing and timely medical, scientific, and public health advice relating to immunization. The Public Health Agency of Canada acknowledges that the advice and recommendations set out in this statement are based upon the best current available scientific knowledge and is disseminating this document for information purposes. People administering the vaccine should also be aware of the contents of the relevant product monograph(s). Recommendations for use and other information set out herein may differ from that set out in the product monograph(s) of the Canadian manufacturer(s) of the vaccine(s). Manufacturer(s) have sought approval of the vaccine(s) and provided evidence as to its safety and efficacy only when it is used in accordance with the product monographs. NACI members and liaison members conduct themselves within the context of the Public Health Agency of Canada's Policy on Conflict of Interest, including yearly declaration of potential conflict of interest.

Introduction

On 15 July, 2005 INFLUVAC^TM, a trivalent, inactivated, subunit influenza vaccine (Solvay Pharma Inc.) was approved for use in Canada for persons ?18 years of age. INFLUVAC^TM has been used in more than 50 countries between 1992 and 2004, with over 130 million doses administered, as a formulation containing thimerosal as a preservative. This update will describe the INFLUVAC^TM formulation approved in Canada, which is thimerosal-free and available only in single dose format. For more detailed information related to the use of influenza vaccines in Canada, readers are referred to the 6^th edition of the Canadian Immunization Guide⁽¹⁾ and the June 2005 NACI Statement on Influenza Vaccination for the 2005-2006 Season⁽²⁾.

INFLUVAC^TM

INFLUVAC^TM is an egg-grown, inactivated, trivalent, subunit sur-face antigen influenza vaccine. Each 0.5 mL dose contains neuraminidase and 15 µg of hemagglutinin antigen for each virus strain present in the vaccine. The antigens included in the vaccine are determined annually based on the World Health Organization recommended composition for the northern hemisphere
vaccine. The virus strains in the vaccine for 2005/2006 are: an A/New Caledonia/20/99 (H1N1)-like strain, an A/California/ 7/2004 (H3N2)-like strain, and a B/Shanghai/361/2002-like strain.

INFLUVAC^TM is thimerosal-free and contains no preservative. Trace amounts of eggs, chicken protein, formaldehyde, cetyltrimethylammonium bromide, polysorbate 80 and gentamicin are present in the vaccine. The vaccine contains the following excipients: potassium chloride, potassium dihydrogen phosphate, disodium phosphate dihydrate, sodium chloride, calcium chloride, magnesium chloride hexahydrate, and water for injection.

Recommended

INFLUVAC ^TM comes as a clear to slightly opalescent suspension in a 0.5 mL pre-filled, single-dose syringe.

Usage

INFLUVAC ^TM is approved for use in adults ?18 years of age.

Dosage

The vaccine (0.5 mL dose) should be administered intramuscularly into the deltoid muscle.

Storage Requirements

The vaccine should be stored, protected from light at 2° C to 8° C in a refrigerator, and should not be frozen. The vaccine should be shaken well before use.

Efficacy and Immunogenicity

Seroprotection is generally obtained within 2 to 3 weeks after immunization and immunity usually lasts for at least 6 months and may last up to 12 months or longer. The efficacy of INFLUVAC ^TM is comparable to the other approved influenza vaccines.

Simultaneous Administration of other Vaccines

INFLUVAC^TM may be given at the same time as other vaccines provided different sites and separate sterile syringes and needles are used.

Adverse Events

Vaccination with INFLUVAC ^TM cannot cause influenza because the vaccine does not contain live virus.

Safety data on INFLUVAC^TM with thimerosal has been summarized in the product monograph from clinical trials and post marketing surveillance conducted up to December 2003.
The safety of thimerosal-free INFLUVAC^TM has been assessed in clinical trials and is also presented in the product monograph. In general, the frequency of reported local and systemic reactions is comparable to that following other approved influenza vaccines.

In clinical trials, pain on contact with the injection site was reported by up to 32% of recipients ?18 years of age in the 3 days after vaccination. Redness, swelling, induration, and restriction in arm movement were reported less frequently. Nine percent of recipients in clinical trials reported headache while malaise, sweating, insomnia, and other systemic complaints were reported by < 5% of vaccine recipients in the 3 days after vaccination. The reactions reported were classified as "mild inconvenience" by the vaccine recipients, with no reports of "moderate or severe inconvenience". Data from other trials of influenza vaccine in adults suggests that these rates of systemic symptoms are not different in vaccine and placebo recipients and are thus not likely to be due to the vaccine⁽³⁾.

As part of ongoing surveillance, reports of Guillain-Barre syndrome (GBS) and any other neurological conditions that occur in the 30 days following the receipt of influenza vaccine are routinely reported. Evidence exists favouring the causal association between the 1976 swine influenza vaccine and GBS in adults, but not in vaccines used subsequent to that season. Forty cases of GBS and one case of possible GBS, classified as ascending neuron paralysis (flaccid paralysis) have been reported following the receipt of 130 million doses of INFLUVAC^TM over the past 11 years. The reported rate of GBS temporally- associated with INFLUVAC^TM is not higher than the expected background incidence of this illness in the Canadian population (20 cases per million). One case of oculorespiratory syndrome (ORS) has been reported following receipt of INFLUVAC^TM. For more general information about and GBS and ORS readers are referred to the June 2005 NACI Statement on influenza vaccination for the 2005-2006 season⁽²⁾ . Other serious but rare adverse events, such as anaphylactic allergic reactions, could occur following the receipt of INFLUVAC?.

Contraindications and Precautions

INFLUVAC ^TM should not be given to people who have had an anaphylactic reaction to a previous dose or who have known IgE-mediated hypersensitivity to eggs or egg products manifested as hives, swelling of the mouth and throat, difficulty in breathing, hypotension, or shock. INFLUVAC^TM should also not be given to people who are hypersensitive to the active substance, any of the excipients, chicken proteins, formaldehyde, cetyltrimethylammonium bromide, polysorbate 80 or gentamicin.

Immunization with INFLUVAC^TM should be deferred in individuals with acute febrile illness until their symptoms have abated. Persons with mild, non-serious illness (e.g. upper respiratory tract infection) may be given vaccine.

References

1. Health Canada. Influenza vaccine In: Canadian immunization guide,6^th ed. Ottawa: Health Canada, 2002;120-127. Cat N^o H49-8/2002E. http://www.phac-aspc.gc.ca/publicat/cig-gci/index.html.

2. National Advisory Committee on Immunization (NACI). Statement on influenza vaccination for the 2005-2006 season. CCDR 2005;31(ACS-6):1-30. http://www.phac-aspc.gc.ca/publicat/ccdr-rmtc/05vol31/asc-dcc-6/index.html.

3. Nichols KL , Margolis KL, Lind A et al. Side effects associated with influenza vaccination in healthy working adults - a randomized placebo-controlled trial. Arch Intern Med 1996;156(14):1546-50.

_______________________________

* Members: Dr. M. Naus (Chair), Dr. T. Tam (Executive Secretary), Dr. S.
Dobson, Dr. B. Duval, Dr. J. Embree, Ms. A. Hanrahan, Dr. J. Langley, Dr. A. McGeer, Dr. K. Laupland, Dr. M-N Primeau, Dr. B. Tan, Dr. B. Warshawsky.

Liaison Representatives: S. Callery (CHICA), Dr. J. Carsley (CPHA), Dr. L. Chapman (CDC), Dr. D. Money (SOGC), A. Honish (CNCI), Dr. B. Larke (CCMOH), Dr. B. Law (ACCA), Dr. M. Salvadori (AMMI Canada), Dr. S. Rechner (CFPC), Dr. J. Salzman (CATMAT), Dr. L. Samson (CPS), Dr. D. Scheifele (CAIRE).

Ex-Officio Representatives: Dr. S. Deeks (CIDPC), Dr. H. Rode (BGTD), Dr. M. Lem (FNIHB), Dr. M. Tepper (DND).

This statement was prepared by Dr. Humaira Khan, Consultant, with the assistance of Dr. Joanne Langley and Jill Sciberras. It was approved by NACI and the Public Health Agency of Canada.

[Canada Communicable Disease Report]