9 October 2015
Vientiane – The Ministry of Health in Lao People’s Democratic Republic has notified WHO of a case of type 1 vaccine-derived poliovirus (VDPV1) in a child with paralysis in Phamueng Village, Bolikhan District, Bolikhamxay Province.
The case was laboratory-confirmed by the National Institute of Infectious Disease, Japan. An 8-year old Hmong boy had onset of fever and limb weakness beginning 7th September. He was admitted to Bolikhamxay Provincial Hospital on 10th September and died on 11th September.
The Ministry of Health is deeply concerned about this case. Prof. Dr Eksavang Vongvichit, Minister of Health, Government of Lao PDR activated the Emergency Operations Centre and Hotline 166 to closely monitor the possible circulation of virus in Bolikhan District following report of this case. He emphasized that it will be important to bring Oral Polio Vaccine (OPV) closer to the people in the affected and neighbouring provinces to contain the circulation of the virus and also to be vigilant to detect any other possible cases. He reiterated that currently in Laos, vaccination with OPV is the only way to prevent both VDPV and polio (e.g., wild type poliovirus).
This comes at a time when the country is preparing to launch use of inactivated polio vaccine (IPV) to prevent polio. Prof. Dr Eksavang said that “The public must be warned about the VDPV and the dangers of not being vaccinated including the risk they pose for themselves and that for the entire community. The affected Bolikhan District has low routine immunization coverage, indicating a cohort of unvaccinated children.”
Lao PDR intensified its efforts to eradicate polio in the 1990s; and the last polio case was reported in October 1996. Lao PDR and all other countries in the WHO Western Pacific Region were officially certified as polio-free in October 2000 and have maintained their polio-free status until now.
Dr Juliet Fleischl, WHO Representative to Lao PDR, said that “This case signifies continuing low levels of immunity in certain pockets of the country and [that it] would require strategic local level interventions and efforts by the National Immunization Programme to address this. WHO has been supporting the Ministry of Health on a joint mission with UNICEF and the US CDC Lao PDR office since the case was reported to conduct a detailed epidemiological investigation in Phamueng Village and neighbouring villages in Bolikhan District. We are considering the option of extending the field assessment to Xiengkhuang and Xaysomboun provinces as there are travel connections from these two provinces to the affected district and they both have low routine immunization coverage rates that could increase the chances of spread to these provinces.
At the same time, a community coverage assessment for OPV will be conducted along with collection of additional stool samples from Phamueng and surrounding villages.”
VDPV cases are rare and usually occur among populations with low vaccination coverage or among immunocompromised individuals. They are called 'vaccine-derived' because they have changed, or evolved, from the live, weakened virus strain contained in OPV. However, when VDPV cases do occur, it is not primarily a problem with the vaccine itself but rather with low vaccination coverage in the population. VDPV strains may spread in communities that are not fully vaccinated against polio, especially in areas where there is poor hygiene, poor sanitation, or overcrowdingand and they can cause paralysis.
UNICEF Representative Ms Hongwei Gao emphasized the importance of immunization. “This sad news reminds us that every child must be immunized against polio. Poliovirus can cause lifelong paralysis. There is no cure but it can be prevented by vaccine. We are now close to a polio-free world, but there is only one way to reach it: take action and immunize all children.”