H3N2 currently dominating - Credit WHO Influenza Rpt #423
#16,888Typically in June and July we are watching the rise of influenza in the Southern Hemisphere in countries like Australia, New Zealand, and South Africa. These outbreaks, while smaller than those seen in the Northern Hemisphere, can often herald the kind of flu season we may see this fall and winter.
After a two-year hiatus - caused primarily by our response to the COVID pandemic (social distancing, masking, etc.) - influenza A returned with renewed vigor to Australia starting last April, peaking unusually early in June (see chart below).
Like Australia, New Zealand appears to have peaked early with their flu season as well. Both nations are dealing with increasing Omicron infections, and a second peak of influenza for either cannot be discounted.
But some countries outside of the Southern Hemisphere are also reporting unusual influenza activity.
Last month, in Southern China: Several Provinces Issue H3N2 Influenza Alerts and again in China NIC Report: Summer Influenza Surge In Southern China, we looked at reports of a strong unseasonable summer flu epidemic in China.
The chart below from China's NIC report of July 4th , shows the unusual summer spike of influenza in Southern China, and suggests it may have peaked as well, although surveillance in China isn't always robust.
The chart below from China's NIC report of July 4th , shows the unusual summer spike of influenza in Southern China, and suggests it may have peaked as well, although surveillance in China isn't always robust.
In recent days we are getting news out of Vietnam, indicating that they too are seeing an unusual rise in influenza, with media reports suggesting that some of these cases - particularly in children - are severe. A sampling of media reports follow:
First, this English language report, from the Voice of Vietnam.
Hanoi on high alert for influenza A infections
Tuesday, 12:06, 19/07/2022
VOV.VN - The capital of Hanoi has been warned to brace for a rise in influenza A cases following an outbreak detected at a Hanoi industrial complex infecting over 100 people in a fortnight.
According to the National Hospital for Tropical Diseases, the hospital confirmed a cluster of influenza A infections, including 20 workers at an industrial park in the suburban district of Dong Anh.
The patients, aged between 20 and 30 years, were admitted to the hospital showing similar symptoms, including headaches, fever, and body aches. Through rapid testing, the majority of patients were found to have influenza A.
Notably, more than 10 children with flu-like symptoms, all of whom are relatives of the workers, later tested positive for influenza A.
Doctors said some of the patient were suffering from serious illness and had to be put on ventilators.
Meanwhile, the Vietnam National Children's Hospital in Hanoi said that the number of influenza A cases has significantly increased recently. The hospital is typically receiving 40 to 50 patients each week, with some of them already contracting pneumonia and suffering from respiratory failure.
Influenza A is caused by the influenza A virus and is one among four types of influenza viruses alongside B, C, and D. It typically causes seasonal flu epidemics and is the only influenza virus known to cause flu pandemics, according to the U.S. Centers for Disease Control and Prevention.
Domestically, the ongoing influenza A outbreak is unusual as it has arrived earlier than expected in contrast to previous years. The disease usually peaks during the winter-spring period when temperatures aren’t high and the air is moist.
Experts say abnormal weather patterns might explain why cases of influenza A are currently so prevalent. In addition, it can also be partly put down to people paying less attention to wearing masks in public spaces, whilst people tend to travel and meet more during summer holidays, resulting in outbreaks.
And this from New Day Online.
(translated)
The number of influenza A cases in Hanoi has increased dramatically
Y TẾ 19/07/2022 11:13
In the past 2 weeks, on average, the Internal Medicine Department of the Center for Tropical Diseases - National Hospital of Pediatrics received 40-50 children admitted to the hospital for treatment of influenza A every week.
Among the hospitalized cases, there are many children with pneumonia, respiratory failure, some still need to breathe oxygen, run ECMO (heart, artificial lung equipment)… The danger is that some cases have been recorded. 3 to 5 days after contracting influenza A, there are symptoms of central nervous system damage, encephalitis, hospitalization in convulsions, lethargy...(Continue . . . )In particular, not only children but also adults with influenza have been hospitalized. In just the past 1 week, the National Hospital for Tropical Diseases has received about 100 patients for examination and treatment due to influenza virus infection, some of them pregnant women. Most of the patients who come to the clinic have an infection in the upper respiratory tract with the following symptoms: high fever, fatigue, sore throat, sneezing, runny nose, even pneumonia.
(translated)
Fear of children suffering from encephalitis complications after influenza A infection increases
Tuesday, 12:33, July 19, 2022
[VOV2] - At the National Children's Hospital, 40-45% of children with influenza A have convulsions, of which about 3-6% have complications of encephalitis. This number is up from previous years.
From the beginning of summer until now, in Hanoi and many northern provinces and cities, the number of influenza A patients is increasing abnormally. Among them, children are one of the most affected subjects.
At the National Children's Hospital, since half a month now, the beds here are always full, sometimes they have to add more beds when they have not been arranged in time. Many cases of hospitalization in the state of fever higher than 39°C does not go down, respiratory failure, pneumonia, influenza, high fever convulsions, organ failure, nerve damage...
There was a case of a pediatric patient in Nghe An with influenza A with severe respiratory failure, lung damage, and transferred to Hanoi for intervention by ECMO.
In addition to the number of patients hospitalized for inpatient treatment, patients with mild influenza A who come to the clinic are prescribed outpatient treatment by doctors. Most children infected with influenza A go to the National Children's Hospital under the age of 5, in Hanoi and some surrounding provinces.
(Continue . . . )
Reports of severe illness, including neurological manifestations, from seasonal flu are concerning but not unheard of. In 2018's Neuroinfluenza: A Review Of Recently Published Studies, we looked at some of these complications (excerpt below).
Although primarily a self-limiting infection of the respiratory tract, for a small subset of cases - most often among children - influenza can present with a variety of subtle, and sometimes profound, neurological symptoms.
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| Credit CDC 2018 COCA Call On Severe Influenza |
We'll obviously be interested in seeing a better characterization of the virus causing this outbreak in Vietnam, but for now it is assumed to be seasonal H3N2.
Influenza seasons are highly unpredictable, and what happens now in Australia, China, or Vietnam doesn't guarantee a severe flu season for Northern Hemisphere this fall.
But between our presumed low community immunity to influenza, new COVID variants - and a lessening of vaccine uptake, social distancing, and face mask use due to `pandemic fatigue' - it would be unwise to ignore the possibility.
