Refresher on rubella
====================

* Erica Weir

I thank Michelle Greiver for her attention to our column on rubella.1 In the first draft of this article Doug Sider and I quoted the Public Health Agency of Canada's advice2 (which appeared to be based on information in the 2002 Canadian Immunization Guide3) that women should avoid pregnancy for 1 month after receiving the rubella vaccine. However, a peer reviewer challenged this statement because one of the bibles on communicable disease, the *Control of Communicable Diseases Manual*,4 states that after immunization for rubella women should prevent pregnancy for 3 months. In the end we decided to relay the more cautious message.

When I try to assess and communicate risk, I usually ask 3 questions: Is there a hazard? If so, what is the magnitude of the adverse outcome? What is the likelihood that the adverse outcome will occur? In this case, there is a hazard associated with immunizing a pregnant woman; the magnitude of the adverse outcome is potentially very great (congenital rubella syndrome) but the likelihood that it will occur is extremely low (bordering on theoretical). Because the potential adverse outcome is so serious we decided to relay the more conservative recommendation. However, given the extremely low likelihood that it will occur, one could as easily argue that advising women to avoid pregnancy for 1 month after immunization is appropriate.

## REFERENCES

1.  1. Weir E, Sider D. A refresher on rubella. CMAJ 2005;172(13):1680-1.
    
    [FREE Full Text](http://www.cmaj.ca/lookup/ijlink/YTozOntzOjQ6InBhdGgiO3M6MTQ6Ii9sb29rdXAvaWpsaW5rIjtzOjU6InF1ZXJ5IjthOjQ6e3M6ODoibGlua1R5cGUiO3M6NDoiRlVMTCI7czoxMToiam91cm5hbENvZGUiO3M6NDoiY21haiI7czo1OiJyZXNpZCI7czoxMToiMTcyLzEzLzE2ODAiO3M6NDoiYXRvbSI7czoyNDoiL2NtYWovMTczLzExLzEzNTkuMi5hdG9tIjt9czo4OiJmcmFnbWVudCI7czowOiIiO30=) 

2.  2. Vaccine preventable diseases — rubella. Ottawa: Immunization and Respiratory Infections Division, Public Health Agency; 2002. Available: [www.phac-aspc.gc.ca/dird-dimr/vpd-mev/rubella\_e.html](http://www.phac-aspc.gc.ca/dird-dimr/vpd-mev/rubella_e.html) (accessed 2005 Oct 14).
    
    

3.  3. National Advisory Committee on Immunization. *Canadian immunization guide*. 6th ed. Ottawa: Health Canada; 2002. Available: [www.phac-aspc.gc.ca/publicat/cig-gci](http://www.phac-aspc.gc.ca/publicat/cig-gci) (accessed 2005 Oct 14).
    
    

4.  4. Chin J, editor. *Control of communicable diseases manual: an official report of the American Public Health Association*. 17th ed. Washington (DC): American Public Health Association; 2000.