BEGIN:VCALENDAR
VERSION:2.0
PRODID:-//talks.cam.ac.uk//v3//EN
BEGIN:VTIMEZONE
TZID:Europe/London
BEGIN:DAYLIGHT
TZOFFSETFROM:+0000
TZOFFSETTO:+0100
TZNAME:BST
DTSTART:19700329T010000
RRULE:FREQ=YEARLY;BYMONTH=3;BYDAY=-1SU
END:DAYLIGHT
BEGIN:STANDARD
TZOFFSETFROM:+0100
TZOFFSETTO:+0000
TZNAME:GMT
DTSTART:19701025T020000
RRULE:FREQ=YEARLY;BYMONTH=10;BYDAY=-1SU
END:STANDARD
END:VTIMEZONE
BEGIN:VEVENT
CATEGORIES:Isaac Newton Institute Seminar Series
SUMMARY:Extinction time for the weaker of two competing SI
S epidemics - Malwina Luczak (Queen Mary Universit
y of London)
DTSTART;TZID=Europe/London:20160908T140000
DTEND;TZID=Europe/London:20160908T150000
UID:TALK67284AThttp://talks.cam.ac.uk
URL:http://talks.cam.ac.uk/talk/index/67284
DESCRIPTION:We consider a simple stochastic model for th
e spread of a disease caused by two virus strains
in a closed homogeneously mixing population of siz
e N. In our model\, the spread of each strain is d
escribed by the stochastic logistic SIS epidemic p
rocess in the absence of the other strain\, and we
assume that there is perfect cross-immunity betwe
en the two virus strains\, that is\, individuals i
nfected by one strain are temporarily immune to re
-infections and infections by the other strain. Fo
r the case where one strain has a strictly larger
basic reproductive ratio than the other\, and the
stronger strain on its own is supercritical (that
is\, its basic reproductive ratio is larger than 1
)\, we derive precise asymptotic results for the d
istribution of the time when the weaker strain dis
appears from the population\, that is\, its extinc
tion time. We further consider what happens when t
he difference between the two reproductive ratios
may tend to 0.

In our proof\, we set out
an approach for establishing a long-term \;flu
id limit approximation for a sequence of Markov ch
ains in the vicinity of a stable fixed point of th
e limit drift equations. \; This is
joint work with Fabio Lopes.
LOCATION:Seminar Room 2\, Newton Institute
CONTACT:info@newton.ac.uk
END:VEVENT
END:VCALENDAR