WHO has published Circulating vaccine-derived poliovirus – Lao People’s Democratic Republic. Excerpt:
On 17 January 2016, the National IHR Focal Point (NFP) of Lao People’s Democratic Republic (PDR) notified WHO of 2 additional cases of vaccine-derived poliovirus type 1 (VDPV1). Both cases are from Longsane district, Xaisomboun Province.
Details of the additional cases
The first new case is a 14-month-old male from Longsane district, Xaisomboun Province. He developed fever on 16 November, progressing to hyporeflexia and asymmetric paralysis in both legs by 18 November. Local health authorities reported the AFP case on 19 November. Vaccination history indicated that the child had received three doses of oral polio vaccine (OPV). On 1 and 3 December, samples of the patient were collected and shipped to the National Institute of Infectious Diseases (NIID) in Japan for testing. On 21 December, the samples tested negative for any polioviruses. However, a sample taken from his asymptomatic sister tested positive for VDPV1. The 14-month old AFP case was classified by the National Coordination Committee as VDPV1 case based on the epidemiological link with the positive contact and also as one additional AFP case from the same district tested positive for VDPV1 indicating the plausibility of VDPV1 circulation in the area.
The second new case is a 40-year-old male from Longsane district, Xaisomboun Province. The patient presented with symptoms on 18 December with hyporeflexia and symmetric paralysis in both legs, but no pulmonary involvement. No fever was reported. The patient had no recent history of any nervous system disease, recent trauma, or animal or insect bites. He had not received any OPV. The Vientiane Provincial Hospital informed the Provincial Health Department of an AFP case on 21 December and a case investigation was conducted on the same day, including stool specimen collection. On 9 January, NIID reported that this patient tested positive for VDPV1.
According to WHO criteria, these two AFP cases are therefore classified as confirmed cVDPV1 cases.