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MEETING OF THE STRATEGIC ADVISORY GROUP OF EXPERTS ON IMMUNIZATION, APRIL 2014
Weekly Epidemiological Record, 23 May 2014,
Conclusions and recommendations, Meeting of the Strategic Advisory Group of Experts on immunization, April 2014
Also available, in French and English, at http://www.who.int/wer/2014/wer8921.pdf?ua=1
Conclusions and Recommendations
The Strategic Advisory Group of Experts (SAGE) on immunization 1 met on 1–3 April 2014 in Geneva, Switzerland. This report provides a summary of the discussions, conclusions and recommendations.
SAGE REPORT, FOUR OF TEN: POLIO ERADICATION
See below the fourth of ten postings on the meeting of the Strategic Advisory Group of Experts on immunization, April 2014. For background documents for the SAGE meeting, go to http://www.who.int/immunization/sage/meetings/2014/april/presentations_background_docs/en/
POLIO ERADICATION
Following the large poliomyelitis outbreaks in the Middle East and the Horn of Africa in 2013, and an expanding outbreak in Central Africa in 2014, Member States are voicing increasing concern about the international spread of poliovirus and have requested additional WHO guidance on recommendations for the vaccination of travellers from countries where poliovirus is circulating. Upon reviewing the relevant scientific evidence, SAGE endorsed updates to the existing WHO recommendations for travellers from polio-infected countries in the WHO publication International Travel and Health (ITH) 2013 as follows:
1. Polio vaccination recommendations for travellers from polio-infected countries should apply to all residents and to visitors of all ages who spend >4 weeks in the country. Several lines of evidence demonstrate that older individuals play an important role in international spread of poliovirus, including observational and challenge studies and documented cases of adult travellers excreting wild poliovirus.
2. In addition to oral poliovirus vaccine (OPV), which is currently recommended in ITH for the vaccination of travellers from polio-infected countries, IPV can be used for booster doses. A recent study from Moradabad, India, demonstrated that 1 dose of bivalent OPV or IPV reduces excretion of poliovirus significantly in people previously given OPV. For people who previously received only IPV, OPV should be the choice for booster if available and feasible.
3. Resident travellers of all ages from polio-infected countries should have received 1 documented additional dose of OPV or IPV a minimum of 4 weeks and a maximum of 12 months before each international travel. Evidence from a number of studies demonstrates that immunologically-naive populations usually attain a maximum immune response within 4 weeks, and intestinal immunity can wane within 12 months. Travellers embarking on last minute/urgent travel that cannot be postponed should nevertheless receive 1 dose of OPV or IPV before departure if they have not received a documented dose of polio vaccine within the previous 12 months.
SAGE recognized the potential social and economic cost associated with the implementation of these recommendations but believes that they would help decrease the risk of outbreaks. In 2013, 60% of the all reported polio cases resulted from long distance importations from polio-endemic countries.
SAGE reviewed the status of IPV introduction globally, which is 1 of the 5 major criteria for judging global readiness for OPV2 withdrawal. 4 SAGE was informed of the outcomes of the February 2014 UNICEF tender, in which one IPV supplier has offered a price of € 0.75 per dose in 10-dose vials (approximately USD 1 per dose) to GAVI-eligible countries and € 1.5–2.4 per dose (approximately USD 2.1–3.3 per dose) for middle-income countries, also in 10-dose vials; another manufacturer offered a price of US$ 1.90/dose in 5-dose vials, for any requesting country. SAGE concurred that these represent the best possible IPV prices in the near term and constitute a firm basis for proceeding with the goal of global IPV introduction by end-2015 as an integral part of the polio endgame strategy. To date, of the 194 WHO Member States, 71 (36%) have introduced IPV and 65 (34%) have decided or declared intent to introduce IPV by end-2015. SAGE reaffirmed the need for all countries to have completed planning for IPV introduction by end-2014. SAGE endorsed the proposed actions by the Immunization Systems Management Group to further accelerate decision-making to introduce IPV in the remaining OPV-using countries, particularly through increased technical assistance, enhanced communications, and potential financial support mechanisms for non-GAVI supported countries in special circumstances. SAGE reinforced the importance of conducting a technical briefing on IPV introduction for OPV-using countries during the WHA in May 2014. SAGE reviewed the progress towards eventual confirmation of a specific date for global OPV2 withdrawal, which requires the absence of persistent circulating vaccine-derived poliovirus type-2 (cVDPV2) for at least 6 months globally. SAGE was alarmed by the persistent VDPV2 circulation in northern Nigeria (since July 2005) and Pakistan (since August 2012), noting that these areas overlap with some of the last wild poliovirus reservoirs in the world. Stopping circulation of both WPVs and VDPVs requires addressing gaps in quality of supplementary immunization activity (SIA), improving routine immunization coverage, increasing access, and using an appropriate mix of trivalent and bivalent OPV over the coming 10 months. SAGE emphasized that the elimination of persistent cVDPV2s by late 2014/early 2015 must be a high priority for global eradication efforts to remain on-track for major milestones of the Polio Eradication and Endgame Strategic Plan 2013– 2018. SAGE urged countries to correct the mix of OPV being used in large scale immunization campaigns in areas with persistent cVDPV2 to ensure that OPV2 can be withdrawn during the 2016 low season for poliovirus transmission, as originally scheduled. SAGE reviewed and endorsed the broad outlines of the proposed approach for mitigating the risk of cVDPV2 emergence at the time of OPV2 withdrawal, including IPV introduction, routine immunization strengthening and preventive trivalent OPV SIAs in Tier 1 and selected Tier 2 countries or parts of countries. The specifics of the approach will be further elaborated by the Working Group for SAGE review in October 2014.