Giuseppe
Emeritus
ECDC. Risk Assessment from the ECDC on the Finding of Vaccine-Derived Polio Virus in Finland.
News from ECDC
[Full PDF Document at LINK. EDITED.]
Risk Assessment from the ECDC on the Finding of Vaccine-Derived Polio Virus in Finland
On February 17, 2009 ECDC published a risk assessment on the finding of vaccine-derived polio virus in sewage water in Tampere, Finland.
In 1988 the Global Polio Eradication Initiative was launched and Europe was declared polio-free by the World Health Organisation in 2002. No cases of paralysis have been attributed to indigenous wild-poliovirus in Europe since 1998.
Vaccine-associated poliomyelitis paralysis (VAPP) is the major adverse event associated with oral poliovirus vaccine (OPV, Sabin vaccine strain).
The first reports appeared in the 1960s shortly after the introduction of the vaccine for widespread use.
The WHO estimates an occurrence of 2-4 cases per one million birth cohort in countries using OPV (250-500 cases worldwide per year) and only in the US 8-9 cases were identified yearly while OPV was still in use.
At present most EU-countries exclusively use inactivated polio vaccine (IPV) in their routine immunisation schedule. However, some countries have only recently moved from OPV to IPV and there are still mixed schedules in a few countries in south-eastern Europe.
An EWRS was posted on 2009-02-10 by Finland reporting the finding of two different vaccine-derived poliovirus (VDPV) strains (serotype 1 and 2, PV1 and PV2) by the WHO Collaborating Centre for Poliovirus Surveillance in Helsinki in a sewage sample collected 2008-12-15 in Tampere, Finland.
Both virus isolates were highly divergent from the corresponding vaccine strains. The VP1 nucleotide sequences similarities of PV1-VDPV to Sabin 1 and PV2-VDPV to Sabin 2 were 86,9% and 87,6% respectively. Concomitantly, Estonia also has isolated VDPV strains in their sewage water.
A vaccine-derived poliovirus (VDPV) is a poliovirus with ≥1% sequence difference compared with OPV. The vast majority of vaccine related virus isolates are OPV-like and show > 99% VP1 sequence identity. 48 laboratories located in 37 European countries are part of the Global Polio Laboratory Network (GPLN), 15 of these conduct environmental surveillance including sewage water samples, and 7 of the latter are within the EU.
Several vaccine-derived poliovirus (VDPV) findings have been reported so far from different EU-countries and adjacent regions. In 2002, one acute flaccid paralysis (AFP) case in Romania was attributed to VDPV. No further cases of paralysis from wild poliovirus or VDPV have been documented in the EU since the European region has been declared polio-free in 2002.
The most likely excretor is an immunodeficient individual, although the individual is not identified. Vaccine-induced antibodies probably neutralize the new isolates, but investigations are pending.
The risk of epidemic outbreaks caused by VDPV in the EU can be minimized by high overall vaccination coverage and continued clinical and laboratory surveillance. Vulnerable groups with low immunity should be addressed particularly, taking into consideration regional and cultural needs. As long as OPV is used in any area of the world VDPV including highly divergent strains will continue to emerge. Therefore encouraging the shift towards exclusively IPV use should be part of the global strategy to eliminate polio.
-
http://ecdc.europa.eu/en/files/pdf/Publications/090217_risk_assessment_polio.pdf
-----
News from ECDC
[Full PDF Document at LINK. EDITED.]
Risk Assessment from the ECDC on the Finding of Vaccine-Derived Polio Virus in Finland
On February 17, 2009 ECDC published a risk assessment on the finding of vaccine-derived polio virus in sewage water in Tampere, Finland.
In 1988 the Global Polio Eradication Initiative was launched and Europe was declared polio-free by the World Health Organisation in 2002. No cases of paralysis have been attributed to indigenous wild-poliovirus in Europe since 1998.
Vaccine-associated poliomyelitis paralysis (VAPP) is the major adverse event associated with oral poliovirus vaccine (OPV, Sabin vaccine strain).
The first reports appeared in the 1960s shortly after the introduction of the vaccine for widespread use.
The WHO estimates an occurrence of 2-4 cases per one million birth cohort in countries using OPV (250-500 cases worldwide per year) and only in the US 8-9 cases were identified yearly while OPV was still in use.
At present most EU-countries exclusively use inactivated polio vaccine (IPV) in their routine immunisation schedule. However, some countries have only recently moved from OPV to IPV and there are still mixed schedules in a few countries in south-eastern Europe.
An EWRS was posted on 2009-02-10 by Finland reporting the finding of two different vaccine-derived poliovirus (VDPV) strains (serotype 1 and 2, PV1 and PV2) by the WHO Collaborating Centre for Poliovirus Surveillance in Helsinki in a sewage sample collected 2008-12-15 in Tampere, Finland.
Both virus isolates were highly divergent from the corresponding vaccine strains. The VP1 nucleotide sequences similarities of PV1-VDPV to Sabin 1 and PV2-VDPV to Sabin 2 were 86,9% and 87,6% respectively. Concomitantly, Estonia also has isolated VDPV strains in their sewage water.
A vaccine-derived poliovirus (VDPV) is a poliovirus with ≥1% sequence difference compared with OPV. The vast majority of vaccine related virus isolates are OPV-like and show > 99% VP1 sequence identity. 48 laboratories located in 37 European countries are part of the Global Polio Laboratory Network (GPLN), 15 of these conduct environmental surveillance including sewage water samples, and 7 of the latter are within the EU.
Several vaccine-derived poliovirus (VDPV) findings have been reported so far from different EU-countries and adjacent regions. In 2002, one acute flaccid paralysis (AFP) case in Romania was attributed to VDPV. No further cases of paralysis from wild poliovirus or VDPV have been documented in the EU since the European region has been declared polio-free in 2002.
The most likely excretor is an immunodeficient individual, although the individual is not identified. Vaccine-induced antibodies probably neutralize the new isolates, but investigations are pending.
The risk of epidemic outbreaks caused by VDPV in the EU can be minimized by high overall vaccination coverage and continued clinical and laboratory surveillance. Vulnerable groups with low immunity should be addressed particularly, taking into consideration regional and cultural needs. As long as OPV is used in any area of the world VDPV including highly divergent strains will continue to emerge. Therefore encouraging the shift towards exclusively IPV use should be part of the global strategy to eliminate polio.
-
http://ecdc.europa.eu/en/files/pdf/Publications/090217_risk_assessment_polio.pdf
-----