Metric analysis

A spike in a COVID metric is raising concerns and reigniting calls for indoor masks in London, Ont.

London’s COVID-19 sewage spike should cause officials to take note, as disease activity in the community hits highs not seen in months, a Western University researcher says.

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London’s COVID-19 sewage spike should cause officials to take note, as disease activity in the community hits highs not seen in months, a Western University researcher says.

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Recently emerging levels of COVID in London’s sewage are on par with the sixth wave in March and April, said Chris DeGroot, assistant professor of mechanical and materials engineering involved in the sewage testing programme.

“We have noticed an increase in (viral) sewage levels since June 30. It has increased quite dramatically from what we were seeing in mid-June when levels were relatively low,” said DeGroot.

The BA.4 and BA.5 sub-variants of the Omicron strain are the main culprits for the recent spike in sewage across the province, he said. London’s top doctor said last week that BA.5 had become the dominant form of COVID-19 circulating in the region over the past two weeks.

Sewage data is now a more complete indicator of the extent of the spread of COVID-19 in the community since the province severely restricted lab testing eligibility during the fifth wave powered by Omicron in December. and January, DeGroot said. There is also no public health mechanism for reporting rapid test results, he said.

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Given the signals appearing in sewage in London – and across the province – DeGroot said government and public health officials should take action.

“The sewage signal typically rises before hospitalizations,” DeGroot said Monday.

“The hope has always been that we would be able to respond to the wastewater data and possibly react with different measures to protect the public. Mask mandates were lifted when case numbers were relatively low. . . . Now that we are seeing a return to higher levels, it would be reasonable to reconsider some of these measures. »

While the summer resurgence in COVID cases is no reason to panic or push for sweeping lockdown-style policies, it’s important to keep a close eye on the burgeoning seventh wave, said Saverio Stranges, president of the epidemiology and biostatistics at the Schulich School of Medicine and Dentistry at Western. .

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“Based on what we’ve seen in other Western European countries that are experiencing this seventh wave a little earlier than Canada, there really hasn’t been the same type of crisis in terms of hospital capacity. than seen in the past,” Stranges said Monday. “The good news is that the vast majority of people infected with the new subvariants appear to have a mild course of disease, mostly upper respiratory symptoms, and not really affecting the lungs.”

However, the higher the percentage of the population that the highly contagious subvariants infect, the more likely the virus is to reach vulnerable people who may be hospitalized or die from it, Stranges said.

People who are unvaccinated, elderly or have health conditions that make them vulnerable to serious consequences from COVID-19 should be especially vigilant as the seventh wave arrives, Stranges said. The general public should consider wearing masks again, especially in crowded indoor public spaces, he added.

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Dr Saverio Stranges
Dr Saverio Stranges

The Western team is analyzing wastewater samples from London’s five wastewater treatment facilities. While not disclosing COVID test results from individual facilities, DeGroot said there were few disparities between the five wastewater treatment plants.

The western team has been testing sewage for the virus since late 2020, but expanded the program in early 2021 and started analyze samples for variants last fall.

Western research teams and other Ontario research teams are tracking the genetic material of the virus in sewage from communities across the province.

The West team has provincial funding for its sewage collection and testing through September and hopes the program will be extended, DeGroot said.

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The Middlesex-London Health Unit reported 111 new cases and one additional death on Monday, totals that reflect tallies from Friday, Saturday and Sunday. The latest death was a woman in her 90s with no connection to a nursing home or long-term care.

The London Health Sciences Center announced on Monday that it had 15 COVID-19 patients in hospital, down 10 from Friday. Five or fewer are in intensive care.

Of the 15 patients, six were admitted to hospital for other reasons but also tested positive for the virus.

  1. Partially treated sewage flows into aeration ponds at the Greenway Pollution Plant in London.  (File photo)

    October 2020: City sewage samples reveal early indicators of coronavirus spread

  2. The Greenway sewage treatment plant (file photo)

    July 2020: London sewage tests showed no trace of COVID-19

  3. Eric Arts is a professor of microbiology and immunology at Western's Schulich School of Medicine and Dentistry and project leader of a Western team testing sewage for the virus that causes COVID-19.  Researchers found viral loads in sewage collected at five local sewage treatment plants were lower than predicted despite a record rise in COVID-19 cases.  (Mike Hensen/The London Free Press)

    December 2021: Omicron does not show up in wastewater like Delta, despite an increase in cases

  4. Mariya Goncheva, a postdoctoral student working in Western University's ImPaKT Level 3 containment lab, demonstrates how staff work under a fume hood inflated with clean air powered by a power supply and HEPA filter she wears at the belt.  (Mike Hensen/The London Free Press)

    April 2022: Inside the London Biosafety Lab where COVID is being studied

  5. (Getty Pictures)

    May 2022: Sixth wave of COVID ‘clearly’ receding in London area: top doctor

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