Highest case count of measles in Ontario is south of London, with overall numbers climbing

The health unit for Oxford County, Elgin County and the City of St. Thomas is dealing with almost half of the measles cases in Ontario with 228 people infected, predominantly in unvaccinated kids. 

The medical officer of health for Southwestern Public Health (SWPH) said Thursday that 28 new cases were reported this past week. He also debunked a misconception circulating in the community that getting the measles provides total immunity. 

"While getting measles can result in natural immunity, being infected with measles carries significant health risks, including pneumonia, brain infections and brain swelling," said Dr. Ninh Tran. "And for pregnant people, measles can cause low birth weight for the baby, preterm birth and miscarriage." 

There have been 470 measles cases since an outbreak began in October, a 120-case increase since March 14, according to Public Health Ontario.

According to its updated case counts released on Thursday, the regional numbers break down like this: 

• Southwestern Public Health: 223. 
• Grand Erie Public Health: 111.
• Huron Perth Public Health: 42.
• South East Health: 35.
• Chatham-Kent Public Health: 20.
• Windsor-Essex County Health: 15.
• Niagara Region Public Health: 9.
• Grey Bruce Health Unit: 8.
• North Bay Parry Sound District: 5.
• Middlesex-London Health Unit: 1.
• Wellington-Dufferin-Guelph: 1.

A measles infection can also have long-term health concerns after it has passed, including seizures, hearing loss, intellectual disability and other lasting neurological problems, Tran said. 

Measles-related pneumonia can cause long-term respiratory issues or scarring in some children. While rare, a fatal brain disorder called subacute sclerosing panencephalitis can develop years after a child has measles. It causes progressive damage to the brain and is not curable, Tran said. 

The latest case count for the SWPH area includes all cases reported since last October, with 19 of them landing patients in hospital. The region has some of the highest numbers as the largest outbreak in 30 years spreads across the province and country, although Tran said he expected to see the virus soon spread to other health units. 

For months, the health authority has warned of possible exposures, usually at walk-in clinics or hospitals where people with measles show up for treatment. It has also been urging people to get vaccinated. 

"The vaccine has been administered in Ontario since the 1970s," said Tran. "It has been a safe and effective way to prevent measles infections for decades." 

In a bid to protect the community, SWPH has expanded its vaccination program to include a first dose for infants aged six to 11 months. 

In London, one case of measles has been recorded in a man in his mid-30s. He was exposed to measles outside the city, officials said. In response to the outbreak, London Health Sciences (LHSC) has implemented new restrictions to visitors that include limiting the number of parents/caregivers allowed to stay with children while they receive care. 

Measles is highly contagious. The virus can remain in an environment for up to two hours after an infected individual has left a specific location. One infected patient can also transmit the disease to up to 20 other people. 

Measles has an incubation period of roughly 10 days, and patients who contract measles initially show symptoms similar to a common respiratory infection, such as the cold or flu.