A recent unseasonal uptick in influenza A and other respiratory viruses in Nova Scotia is likely related to the lifting of COVID-19 measures such as masking, doctors say.
There were 36 cases of influenza A identified during the first week of June — the most in any week so far this year. Another spike of 32 cases was reached in early May.
Both peaks fall outside the normal flu season in the province, which is most intense from about December to April. There are typically fewer than five cases of influenza A or B identified each year in early June, and often there are none.
Reports released by the province also show a steady increase in emergency department visits due to influenza-like illnesses since mid-May, a trend which is continuing into June.
Dr. Katrina Hurley, a physician and the chief of the emergency department at the IWK Health Centre, says about 10 per cent of kids coming to emergency are screening positive for influenza-like illnesses that are not COVID-19 — much higher than the usual figures of one to two per cent for this time of year.
"June is usually the time when things are turning around — we're seeing, you know, kids fall off their bikes, but not having trouble breathing usually," she said. "We're hustling like it's peak flu season right now and this is not normal."
Hurley said a variety of non-COVID-19 viruses are being identified, including influenza A, rhinovirus, human metapneumovirus, enterovirus and parainfluenza.
The removal of mandatory masking is likely contributing to the surge, Hurley said.
"Masking protected us not only from COVID, it protected children from essentially everything. And so now that the masks are off and things are circulating, you have this whole cohort of children under the age of two, two and a half, who have not been exposed to any of these illnesses before," she said.
"The number of children I'm seeing right now who attend daycare and saying that they're just getting illness after illness after illness is the story that I'm hearing. I went two years without diagnosing an ear infection and now I'm seeing them almost every shift. So it's all the things that used to plague children and used to be a normal part of childhood disappeared, and now they're back."
Dr. Tanya Munroe, an emergency department doctor at Colchester East Hants Health Centre, also believes the move to optional masking, particularly in schools, is a likely culprit for the increase in respiratory virus circulation.
"When you look at the schools, where they hung on to the mask mandate longer than the general public, which was a good idea, now that it's off among that population, that's a pretty good petri dish for a lot of viruses to spread."
Munroe said it's possible that the apparent increase in confirmed non-COVID-19 respiratory virus cases is due to increased testing for them.
She said, prior to COVID, if a patient went to an emergency department with a cough, cold, runny nose, fever or muscle aches and pains, they'd likely only get swabbed if they were in a high-risk population such as a long-term care resident, or if they required hospital admission.
Now, as patients in emergency departments are swabbed to rule out COVID-19, those swabs are also processed for influenza A, B and respiratory syncytial virus.
"So we are case-finding because we're looking in a way we wouldn't historically have done," Munroe said.
Munroe also wondered whether uptake of the flu shot had faltered this season, leading to greater spread of influenza. The Department of Health and Wellness was not able to provide statistics on how many Nova Scotians received their flu shots this year.
Dr. Shelley Deeks, Nova Scotia's deputy chief medical officer of health, agreed the lifting of COVID-19 restrictions could be driving the transmission of other viruses.
She said the late-season spike in influenza A could also be caused by the waning effectiveness of flu shots, many of which were delivered last fall, as well as the limited efficacy of the vaccine against what turned out to be the dominant strain of the virus.
Nova Scotia is far from alone in experiencing a surge in flu cases outside of the normal season. Deeks said that trend has been identified across the country, but national numbers appear to have peaked a few weeks ago.
'We're in unknown territory'
Munroe is has some optimism that the circulation of respiratory viruses will decrease with the onset of summer as people spend more time outdoors.
Hurley is a bit more hesitant.
"I wouldn't use the word that I'm optimistic," she said. "I'm hopeful that this is going to shift and we're going to have a bit of a spell where we get a break over the summer before it ramps back up when kids return to school.
"But I feel like what the graphs and the data show me is that we can't predict what's going to happen. I think we're in unknown territory."
The IWK emergency department currently has about 40 per cent more patients than usual this time of year, so Hurley urged people to be understanding if they face longer waits than normal.
"We want to provide them good care and we're doing the best we can with the resources we have."