  We investigate final outcome properties of an SIR (susceptible $\to$
infective $\to$ recovered) epidemic model defined on a population of large
sub-communities in which there is stronger disease transmission within the
communities than between them. Our analysis involves approximation of the
epidemic process by a chain of within-community large outbreaks spreading
between the communities. We derive law of large numbers and central limit type
results for the number of individuals and the number of communities affected
and the so-called severity of the outbreak. These results are valid as the size
of communities tends to infinity, with the number of communities either fixed
or also tending to infinity. The weaker between-community connections lead to
randomness even in the law of large numbers type limit. As part of our proofs
we also obtain a new result concerning the rate of convergence of the expected
fraction infected in a standard SIR epidemic to its large-population limit.
