Parameter	Definition	Default value
$\phi$	Probability of cross-protection given infection with either strain	0 or 0.6
$\omega$	Maximum vaccine efficacy (probability of protection against perfect antigenic match)	0.95
${\alpha }_1$	Probability vaccine fails to elicit immunity against strain 1 (due to antigenic mismatch)	0
${\alpha }_2$	Probability vaccine fails to elicit immunity against strain 2 (due to antigenic mismatch)	$1-\phi$