Corrected Lab Result Shows March 12th Measles Case In Simcoe Muskoka Did Not Have Measles


On March 26, the Simcoe Muskoka District Health Unit (SMDHU) was notified by Public Health Ontario’s (PHO) laboratory that due to laboratory error, the case of measles that had been lab-confirmed positive on March 12, based on symptoms and a positive urine measles laboratory result by PHO’s laboratory, is in fact negative for the measles virus.

“With this new information of the negative lab result, we believe that that individual was not infected with measles and that there has not been any public exposure to measles resulting from this individual’s illness,” said Dr. Charles Gardner, medical officer of health. “We recognize that notifying the public of what we believed to be a positive measles case in our area created worry, anxiety and disruption for some, and we regret this. We do know that, despite best efforts, on rare occasions laboratory errors can occur. We are working closely with the PHO’s laboratory to do all that we can to ensure that such an incident does not occur again.”

Measles is a highly contagious viral infection that spreads very easily through airborne transmission. The measles virus can live in the air or on surfaces for up to two hours. Symptoms of measles begin seven to 21 days after exposure and include fever, runny nose, cough, drowsiness, and red eyes. Small white spots appear on the inside of the mouth and throat but are not always present. Three to seven days after symptoms begin, a red, blotchy rash appears on the face and then progresses down the body. The risk of transmission to those vaccinated with two doses is low, and when it does occur tends to show a reduction in the severity of these symptoms.

“Although we are relieved for the individual involved, and for all Simcoe Muskoka residents, that this case has now been confirmed as negative, we know that measles is still active in Ontario at this time and the potential remains for new cases to arise, especially given the increase in Ontarians travelling to areas in the world that have higher numbers of measles cases,” said Dr. Gardner. “This is why we continue to advise individuals to keep up to date with their routine immunizations, including measles, mumps and rubella (MMR) vaccination.”

The risk of measles is low for people who have been fully immunized with two doses of measles vaccine or those born before 1970; however, many children have been delayed in receiving their routine childhood immunizations and people who have not had two doses of measles vaccine are at higher risk of contracting the disease.

People who do get sick usually recover without treatment, but measles can be more severe for infants, pregnant women, and those with compromised immune systems. Possible complications include middle ear infections, pneumonia, diarrhea, or encephalitis (swelling of the brain) and occasionally death in the very young. Even individuals who are up to date with the measles vaccine should watch for symptoms of measles for 21 days after exposure.

For more information about measles, please visit or call Health Connection at 705-721-7520 or 1-877-721-7520, Monday to Friday between 8:30 a.m. to 4:30 p.m. to speak with a public health professional.


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