{"id":724,"date":"2015-05-21T11:00:41","date_gmt":"2015-05-21T11:00:41","guid":{"rendered":"http:\/\/stg-blogs.bmj.com\/bmjebmspotlight\/?p=724"},"modified":"2017-08-21T11:49:57","modified_gmt":"2017-08-21T11:49:57","slug":"primary-care-corner-with-geoffrey-modest-md-measles-and-immunosuppression","status":"publish","type":"post","link":"https:\/\/stg-blogs.bmj.com\/bmjebmspotlight\/2015\/05\/21\/primary-care-corner-with-geoffrey-modest-md-measles-and-immunosuppression\/","title":{"rendered":"Primary Care Corner with Geoffrey Modest MD: Measles and immunosuppression"},"content":{"rendered":"

By: Dr. Geoffrey Modest\u00a0<\/strong><\/p>\n

Of late, it seems that I\u00a0have been mostly trashing immunization, specifically the\u00a0pertussis component of Tdap. so, I thought I should highlight a really interesting (to me)\u00a0article from the journal Science on the mysteries of the remarkably successful measles vaccine\u00a0(see doi:\u00a010.1126\/science.aaa3662). Here is a brief review of the article.<\/p>\n

–mass measles vaccination in the past reduced childhood mortality by 30-50% in resource-poor countries and up to 90% in the most impoverished countries. T<\/strong>his benefit could not be explained simply by preventing measles infection alone<\/strong>.<\/p>\n

–measles virus (MV)\u00a0infection is associated with profound immunosuppression, and recent data challenge the prior notion\u00a0that this is\u00a0a transient phenomenon:<\/p>\n

\u00a0\u00a0\u00a0\u00a0–data (mostly animal) suggest that measles infection leads to a loss in immune memory cells, and that this is prevented by vaccination<\/p>\n

–in\u00a0macaques,\u00a0measles infection leads to systemic depletion of lymphocytes and reduced innate immune cell proliferation. MV\u00a0leads to replacement of “the previous memory cell repertoire with\u00a0measles virus-specific lymphocytes, resulting in ‘immune amnesia’ to non-measles pathogens”. Recovery of these memory cells requires restimulation by the appropriate\u00a0antigens<\/p>\n

–in the current study, they looked at 4 sets of data from resource-rich countries with adequate data on the pre- and post-measles vaccination period (England, Wales, US, Denmark) to test the hypothesis that MV\u00a0infection leads to immune amnesia, findings:<\/p>\n

–there was a significant\u00a0correspondence\u00a0between measles disease\u00a0incidence and mortality overall<\/p>\n

–there was significant reduction in nonmeasles infectious disease\u00a0mortality associated with the\u00a0introduction of the measles\u00a0vaccine (vaccination programs occurred at different times in the different countries, 20 years later in Denmark)<\/p>\n

–the data from England and Wales suggested that the duration of MV-immunomodulation lasted 28\u00a0months on average. In the US data it was 31 months, and 30 months in Denmark<\/p>\n

–this time lag was consistent for age groups 1-4 yo and 5-9 yo.<\/p>\n

–the increase in mortality\u00a0was consistent for different diseases (pneumonia, dysentery\/diarrhea) and different\u00a0organisms (bacteria –eg strep, pneumococcus, typhoid, meningococcus — as well as fungal and viral pathogens), though not so for septicemia and rubella, which seemed to have shorter periods of immunologic amnesia (3 months\u00a0and 12 months, respectively). This suggests a pretty global immune amnesia.<\/p>\n

–looking at pertussis,\u00a0which is not associated with immunosuppression,\u00a0\u00a0vaccination did not influence non-pertussis mortality in\u00a0England and Wales<\/p>\n

–one interesting\u00a0corollary of the above finding is that MV infection could diminish the herd immunity effect (ie, population immunity) from other infections (ie, not only increase the susceptibility of an individual infected with MV to a non-measles\u00a0infection, but also of a non-measles infection being more likely to\u00a0spread\u00a0throughout the population,\u00a0even to those who did not get MV but are susceptible to other infections). Or to put that more concretely, if you need 80% immunity in a community to prevent the spreading of infectious disease XXX, and the level is 90% in that community, a measles outbreak may bring that immunity level down to 50-60%, making the whole community more susceptible to the spread of infection XXX.<\/p>\n

So, again, the above data challenge the usual (simplistic) understanding about vaccination — its effects are not simply increasing immunity to\u00a0its targeted specific microbial species, but that any immunologic\u00a0manipulation may have collateral effects on the functioning of the immune system overall\u00a0(sort of like medication effects — the adverse effects found are just collateral effects on other cells\u00a0in the body, and are above and beyond the desired targeted effects). What are the implications of this?<\/p>\n

–the reverse could be true: vaccination could conceivably\u00a0cause\u00a0profound alterations of the immune system or other systemic effects which undercut\u00a0the protection from the vaccine. Examples might include the earlier rotavirus vaccine, associated\u00a0with documented increased risk of\u00a0intusseseption in kids;\u00a0and even the measles vaccine, which is associated with enough immunosuppression itself that you need to wait 4-6 weeks afterwards\u00a0to get reliable results from\u00a0a PPD test.\u00a0So, it is important\u00a0to look at even more than vaccine-specific clinical benefits\u00a0but at a much larger picture (such as the overall mortality effects noted in\u00a0the measles study above)<\/p>\n

–there may not be much of a correlation between a robust antibody response and clinical disease protection. For example\u00a0the recent dengue vaccine achieved robust immunologic response from all 4 serotypes included in the vaccine,\u00a0but there was no significant clinical protection in those with\u00a0serotype\u00a02\u00a0infection.<\/p>\n

–and, yet again, this measles article brings up the importance of our always challenging and modifying our understanding of physiologic processes.<\/p>\n","protected":false},"excerpt":{"rendered":"

By: Dr. Geoffrey Modest\u00a0 Of late, it seems that I\u00a0have been mostly trashing immunization, specifically the\u00a0pertussis component of Tdap. so, I thought I should highlight a really interesting (to me)\u00a0article from the journal Science on the mysteries of the remarkably successful measles vaccine\u00a0(see doi:\u00a010.1126\/science.aaa3662). Here is a brief review of the article. –mass measles vaccination […]<\/p>\n

Read More…<\/a><\/p>\n","protected":false},"author":148,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"_jetpack_memberships_contains_paid_content":false,"footnotes":""},"categories":[14283],"tags":[],"class_list":["post-724","post","type-post","status-publish","format-standard","hentry","category-archive"],"jetpack_featured_media_url":"","jetpack_sharing_enabled":true,"_links":{"self":[{"href":"https:\/\/stg-blogs.bmj.com\/bmjebmspotlight\/wp-json\/wp\/v2\/posts\/724","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/stg-blogs.bmj.com\/bmjebmspotlight\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/stg-blogs.bmj.com\/bmjebmspotlight\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/stg-blogs.bmj.com\/bmjebmspotlight\/wp-json\/wp\/v2\/users\/148"}],"replies":[{"embeddable":true,"href":"https:\/\/stg-blogs.bmj.com\/bmjebmspotlight\/wp-json\/wp\/v2\/comments?post=724"}],"version-history":[{"count":0,"href":"https:\/\/stg-blogs.bmj.com\/bmjebmspotlight\/wp-json\/wp\/v2\/posts\/724\/revisions"}],"wp:attachment":[{"href":"https:\/\/stg-blogs.bmj.com\/bmjebmspotlight\/wp-json\/wp\/v2\/media?parent=724"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/stg-blogs.bmj.com\/bmjebmspotlight\/wp-json\/wp\/v2\/categories?post=724"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/stg-blogs.bmj.com\/bmjebmspotlight\/wp-json\/wp\/v2\/tags?post=724"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}