Discussions marquées : Dengue

Strategic Advisory Group of Experts (SAGE) on Immunization April 2016 meeting report

Melanie Marti Publié dans :
The SAGE April 2016 meeting report has been published today in the WHO Weekly Epidemiological Record. SAGE reviewed relevant data and evidence, advised and made recommendations on various complex and critical issues including the:

Use of dengue vaccine;
Progress towards polio eradication;
Implementation of immunization in the context of Health Systems Strengthening and Universal Health Coverage;
Second-year-of-life immunization platform;
Missed opportunities for vaccination; and
Pre-empting and responding to vaccine supply shortages.

You can download the meeting report at http://www.who.int/wer/2016/wer9121/en/.

Weekly epidemiological record: SAGE special (No. 20 , 2013 , 88 , 201–216)

Moderator Publié dans :
The Strategic Advisory Group of Experts (SAGE) on Immunization was established by the Director-General of the World Health Organization in 1999. It is the principal advisory group to WHO for vaccines and immunization and is concerned not just with childhood vaccines and immunization, but all vaccine-preventable diseases.

The Group met in Geneva from 9 April to 11 April 2013. The topics listed below were discussed. Please read the WHO Weekly Epidemiological Report for a detailed description of the discussion and recommendations.

Report from the WHO Department of Immunization, Vaccines and Biologicals
The report focused on: (i) the Global Vaccine Action Plan (GVAP) roll-out; (ii) the strengthening of routine immunization and efforts to integrate immunization and other child health interventions; and (iii) the changing epidemiology of measles.

Report from the GAVI Alliance
The report provided an update on: (i) the processes and timelines for developing the next Vaccine Investment Strategy (for the period 2015–2020) beyond existing commitments, (ii) the preliminary Board discussions regarding GAVI’s potential role in supporting the GPEI, including supporting inactivated polio vaccine (IPV)introduction and potential innovative financing instruments for mobilizing resources, and (iii) the preparations for the next GAVI replenishment round in 2014.

Report from the Global Advisory Committee on Vaccine Safety (GACVS)
A report of the December 2012 GACVS meeting was presented. SAGE acknowledged the detailed review and the recommendations of GACVS on the safety profile of varicella vaccines, risk of narcolepsy and Guillain-Barré syndrome with influenza vaccines, and the safety of dengue vaccines.

Report from the Immunization Practice Advisory Committee (IPAC)
A report of the April 2013 IPAC meeting was presented. SAGE endorsed IPAC’s ongoing contributions to the development of the “Reaching Every Community” toolkit and to the immunization session checklist. SAGE supported these additional tools and validated IPAC’s proposal to pilot test the tools before wide-spread implementation.

Dengue vaccines
... There are unique challenges for dengue vaccine development, including a lack of animal disease models, absence of immunological correlates of protection, and a potential immunopathological component in severe disease, as previous infection with dengue is a risk factor for severe disease upon secondary infection by a heterologous dengue virus. There are currently 5 vaccine candidates in human trials, all of which are tetravalent vaccines designed to protect against all 4 dengue serotypes; 3 are chimeric live attenuated vaccines and 2 are inactivated or subunit vaccines. Several other vaccine candidates are in the preclinical stage of development. SAGE reviewed the results of the Phase IIb trial of the lead vaccine candidate, a tetravalent live attenuated vaccine.

Polio eradication
SAGE commended the GPEI on remarkable continued progress made towards decreasing wild poliovirus transmission in the remaining endemic areas, especially in view of significant difficulties. 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 IPV in up to 130 countries that use OPV over a relatively short period of time represented a major and unprecedented challenge.

Yellow fever vaccination
Based on currently available surveillance data, SAGE concluded that vaccine failures are extremely rare and do not cluster as time increases after immunization. A single dose of YF vaccine is sufficient to confer sustained immunity and life-long protection against yellow fever disease and a booster dose of YF vaccine is not needed. Surveillance in endemic countries and clinical studies may possibly identify specific risk groups (such as infants or HIV-infected patients) that could benefit from a second primary or booster dose. SAGE requested WHO to revisit the IHR provisions relating to the period of validity for international certificates for vaccination against YF.

Non-specific effects of vaccines on mortality
SAGE previously requested that WHO review the evidence concerning the possible non-specific mortality effects of vaccines included in the routine infant immunization schedule. SAGE has now established a working group to review data on non-specific effects and consider whether current evidence is sufficient to merit adjustments in policy recommendations, or may warrant further scientific investigation and if so, to outline a path towards obtaining unequivocal evidence that would inform future robust, evidence-based adjustments in immunization policies, if warranted. SAGE recognized that there have been previous reviews on this topic by WHO committees, including reviews by the GACVS between 2000 and 2008.

SAGE was asked to review the protocols for 2 systematic reviews to assess the possible non-specific effects of vaccines: one regarding the epidemiological mortality studies and the other on human immunological studies of non-specific effects of vaccine on mortality in children
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