Measles and Rubella, Conclusions and Recommmendations of the October 2015 Meeting of the SAGE

Sunday, 13th of December 2015

Conclusions and Recommendations of the October 2015 Meeting of the SAGE

 

Excerpt from the full report of the SAGE, available in French and English at http://www.who.int/wer/2015/wer9050.pdf?ua=1

 

Measles and rubella

Annually >1 million measles-related deaths are prevented globally through measles vaccination.

However, outbreaks of measles continue to occur and progress towards global control targets and regional elimination goals have plateaued. SAGE reaffirmed its previous assessment that the 2015 global measles control milestones as well as regional measles and rubella elimination goals are off-track (except in the Americas). SAGE supported the conduct of a midterm review of the global measles and rubella strategic plan to better understand why targets are being missed and propose measures to accelerate progress.

Recent outbreaks of measles in countries achieving high level control, or near elimination, have had a bimodal age distribution, involving infants below the recommended age for vaccination, and adolescents and young adults. 

Infants of mothers with vaccine-induced immunity lose passive immunity to measles approximately 3 months earlier than infants of mothers with immunity acquired via measles disease. A systematic review found that MCV given from 6 months of age is immunogenic, effective and safe. Vaccine effectiveness increases with the infants age at vaccination. Some evidence of a blunted response to MCV2 after MCV1 in infants aged <9 months was found with respect to geometric mean titres and avidity, but not for the proportion seropositive or for cellular immunity.

SAGE concluded that the available evidence supports use of MCV before 9 months of age and recommends that infants from 6 months of age receive a dose of measles containing vaccine in the following circumstances: (1) during a measles outbreak as part of intensified service delivery; (2) during SIAs in settings where risk of measles among infants remains high (e.g. in endemic countries experiencing regular outbreaks); (3) for internally displaced populations and refugees, and populations in conflict zones; (4) for individual children at high risk of contracting measles (e.g. contacts of known measles cases or in settings with increased risk of exposure during outbreaks such as day-care facilities); (5) for infants travelling to countries experiencing measles outbreaks; and (6) for infants known to be HIV-positive (see 2009 measles vaccine position paper).

Because immunogenicity and effectiveness are lower than for doses administered at a later age and concern about the long-term effectiveness of an early 2-dose schedule, MCV administered before the age of 9 months should be considered a supplementary dose and recorded on the childs vaccination record as “MCV0”. 

Children who receive a MCV0 dose should then receive subsequent measles-containing vaccines at the recommended ages according to the national schedule. Available evidence on safety and immunogenicity of rubella and mumps-containing vaccines support their use from 6 months of age. Countries using measles-rubella (MR) or measles, mumps and rubella (MMR) in their national schedule should use the combined vaccine rather than measles-only formulations in children aged <1 year. SAGE recognizes that this is an off-label use and recommends that national programmes do not restrict the use of the vaccine in the <1 year age group.

SAGE recommended further clinical, immunological, epidemiological and modelling studies regarding the impact of different measles vaccination schedules.

The multi-country analysis of the impact of SIA strategies and comparison of surveillance and susceptibility data are still at an early stage. Mathematical modeling suggests a high quality measles SIA (reaching >90% of susceptible children) targeting children aged <5 years is equally effective and more cost-efficient than a lower quality wider age range SIA (e.g. targeting children aged <10 years reaching >70% of susceptible children). An introductory MR SIA algorithm to guide countries on which age groups to target appears promising. Further work is needed to confirm applicability and allow an integrated measles-rubella approach.

SAGE reviewed evidence indicating that an increasingly large number of HIV-infected children will receive antiretroviral therapy and that these children are at increased risk of measles because of poor antibody responses following vaccination prior to initiation of highly active antiretroviral therapy (HAART). While HAART does not restore measles immunity from previously received vaccine doses, it enables higher and more prolonged antibody responses following revaccination. 

SAGE recommended that an additional dose of MCV be administered to HIV-infected children receiving HAART following immune reconstitution. If CD4+ T lymphocyte counts are being monitored, an additional dose of MCV should be administered when immune reconstitution has been achieved, e.g. when the CD4+ T lymphocyte count reaches 20%–25%. Where CD4+ T lymphocyte monitoring is not available, children should receive an additional dose of MCV 6–12 months after initiation of HAART. Current evidence is insufficient to recommend an additional dose for children who start HAART prior to the first dose of MCV.

A supplementary dose of MCV should be considered soon after diagnosis of HIV infection in children older than 6 months who are not receiving HAART, and for whom the risk of measles is high, with the aim of providing partial protection until they are revaccinated after immune reconstitution with HAART. 

SAGE requested evidence on the need for measles revaccination of HIV-infected adolescents and adults. Further research is needed to monitor the long-term immune responses to measles vaccine in HIV-infected children revaccinated after starting HAART and in HIV-infected children starting HAART prior to receiving their first dose of MCV.