Table 1. Selected epidemiological parameters of the 2007 and 2017 chikungunya outbreaks in Italy.

		2007	2017
Infection	Probable cases	337	499	[19,20]
	Confirmed cases	217	270	[19,20]
	Index case notified	yes	no	[7,9]
Spread	N primary foci	2	3	[7,19,48]
	Other municipalities with incident cases	5	16	[7,19,48]
	Spread to other regions	no	yes	[19,21,48]
	Spread to other countries	no	yes	[19,21,48]
Duration	Time from first to last autochthonous case	140 days	134 days	[7,19,48]
	First notified symptom onset	4 July	26 June	[7,19,48]
	Last notified symptom onset	20 November	5 November	[7,19,48]
	Index case	23 June	unidentified	[7,19,48]
Epidemiology	R0 basic reproductive number	range: 1.8–6	range: 1.5–2.6	[6,26–28]
	Attack rate per foci (%)	5.4; 2.5	0.3; 4.3	[7,20,28]
	Vector/host ratio	10–35	1.9–7.3	[6,26,27]
Vector competence	Infection rate (%)	range: 40–100	range: 50–100	[30]
	Transmission rate (%)	range: 50–86	range: 75–80	[30]
	Transmission efficiency (%)	41	42	[30]