Session #1 - Open Session

VRBPAC Teleconference March 6, 2002 Preliminary Summary

(revised 3/27/02)

Session #1-Open Session

B Strain Selection for Influenza Virus Vaccine for the 2002-2003 Season

The panel heard presentations on strains of circulating influenza virus. After discussion, the committee made the following recommendations for the influenza virus strains to be included in vaccine for use during the 2002-2003 season in the United States.

The January 30, 2002 recommendation of the advisory committee regarding the vaccine strain A composition was to retain both the H1N1, A/New Caledonia/20/99, and the H3N2, A/Panama/2007/99, influenza strains used from the current 2001-2002 season.

Based on information about the appearance and epidemiology of new influenza virus variants, responses to current vaccines, and the availability of strains and reagents needed for manufacturing, the committee made the recommendation to change the B component of the current 2001-2002 vaccine to a new B strain formulation.

The committee recommended changing the influenza B virus component to a B/Hong Kong/330/2001-like virus strain. The 2002-2003 vaccine recommendation from the committee would be to continue with a trivalent vaccine consisting of:

1) H1N1, A/New Caledonia/20/99,

2) H3N2, A/Panama/2007/99 (an A/Moscow/10/99-like virus),

3) B/Hong Kong/330/2001-like virus strain

The committee discussed the pros and cons of changing to a quadrivalent vaccine. The committee discussed retaining the current 2001-2002 B/Sichuan/379/99-like virus; and adding to, in addition, the B/Hong Kong/330/2001-like virus to create a quadrivalent vaccine. Issues of efficacy and safety in humans would have to be evaluated for a quadrivalent vaccine containing either 15 ug of HA of each of 4 strains (H1N1, H3N2, and 2 different B strains) or 15 ug of HA of each of the two A strains (H1N1, H3N2) and 7.5 ug of each of two B strains. More information is needed before recommending a quadrivalent vaccine. The following points were raised regarding the barriers in using a quadrivalent vaccine for 2002-2003:

1) There is currently insufficient data to support the safety and efficacy of using a quadrivalent vaccine.

2) Clinical studies are needed to evaluate the safety and efficacy of a quadrivalent vaccine.

3) A quadrivalent vaccine containing 15 ug of HA of each of 4 strains would reduce the total number of doses available for distribution in vaccine production.

4) Creating a quadrivalent vaccine would delay the 2002-2003 vaccine availability.

The committee again strongly recommended that strain surveillance data be obtained from a pediatric population to study pediatric immunogenicity and efficacy of the influenza vaccine, as this group is relatively unprimed and may display a distinct pattern of susceptibility to the circulating strains compared to the adult population.