Immunization, Vaccines and Biologicals

Summary of the SAGE April 2013 meeting

Meeting participants sat at the table during the SAGE meeting
WHO/Caroline Scudamore

SAGE commended the Global Polio Eradication Initiative (GPEI) on the remarkable continued progress made towards decreasing wild poliovirus transmission in the remaining endemic areas, especially in view of serious challenges. The programme has also intensified systematic preparations for the withdrawal of oral polio vaccine type 2 (OPV2) along several key workstreams. SAGE recognised that the need to introduce inactivated polio vaccine (IPV) into up to 130 OPV-using countries over a relatively short period of time represented a major and unprecedented challenge.

SAGE noted with concern the extraordinary challenges faced by GPEI with the recent serious security problems encountered in Pakistan and Nigeria and strongly condemned the targeting and murder of polio workers. Security concerns are now the key impediment to wild virus eradication in critical remaining endemic areas. SAGE strongly supports initiatives ongoing in both countries to respond to and resolve the security problems affecting the polio programme. SAGE applauded the promising recent effort in the Middle East to engage Islamic scholars and religious leaders and establish an Islamic leader task force to assist in communicating with local religious and community leaders in the remaining endemic areas. There is hope that these efforts will lead to improved and safer access of vaccination teams to children and increase community acceptance of OPV and other Expanded Programme on Immunization (EPI) vaccines.

SAGE noted that the proposed timeline leading to final OPV2 withdrawal (which may occur as early as April 2016) is ambitious but both achievable and urgently needed to ensure the success of the programme. Initiating and then completing OPV2 withdrawal as soon as feasible is critical to reduce the disease burden caused by circulating vaccine-derived poliovirus, to avoid global programme fatigue and control programme cost, and to shorten the overall timeline towards the GPEI goal through the sequential removal of Sabin strains to boost global immunity against the remaining wild virus serotypes, and, potentially, to accelerate wild virus eradication in any areas of residual transmission.

SAGE agreed with the activities towards OPV2 withdrawal, as outlined by the SAGE Polio working group. This will require SAGE to review suggested IPV schedules, a draft type 2 virus response protocol for the period after OPV2 cessation and a draft IPV supply and financing strategy at the next meeting in November 2013. SAGE supported a technical briefing on key OPV2 withdrawal issues at the WHA 2014, in advance of a potential World Health Assembly resolution in 2015 on a target date for the last date of OPV2 in routine immunization programmes globally.

SAGE highlighted several important remaining caveats for the programme to successfully achieve OPV2 withdrawal according to the timeline presented. These include the need to develop more detailed workplans for each of the main workstreams on critical OPV2 withdrawal pre-requisites, and the preparation of contingency plans for responding to possible scenarios of delays or other problems.

With respect to yellow fever vaccination, SAGE reviewed the need for a booster dose every ten years. Based on currently available data, a single dose of yellow fever vaccine is sufficient to confer sustained life-long protective immunity against yellow fever disease. Therefore, a booster dose of yellow fever vaccine is not needed to maintain immunity.

After reviewing country experiences, SAGE noted an increase in the proportion of measles cases in older age groups, particularly adolescents and adults, and the increased risk of complications of measles when it occurs in adults (e.g., encephalitis). SAGE reaffirmed the principle that measles immunization strategies should be adapted according to the country’s control goal, the epidemiological situation, and the programme’s capacity to achieve high coverage. In particular, measles supplementary immunization activities (SIAs) should be tailored to cover all susceptible age groups as indicated by the age distribution of measles cases and vaccine coverage gaps.

SAGE noted the significant efforts by WHO, the GAVI Alliance and many partners, as well as countries themselves, to improve co-ordination and integration of services, but that far more needs to be done to strengthen the national immunization systems and to integrate programmes such as the GPEI into routine services.

SAGE recommended the following regarding the Haemophilus influenza type b (Hib) vaccine immunization schedule. Any one of the following schedules may be used: three primary doses without a booster (3p+0), two primary doses plus a booster (2p+1) and three primary doses with a booster (3 p+1). The interval between doses should be at least 4 weeks if 3 primary doses are given and at least 8 weeks, if 2 primary doses are given.

The report of the meeting will be published in the WHO Weekly Epidemiological Record on 17 May 2013. The meeting documents — including presentations and background readings — can be found below: