Have You had the flu this year? I didn’t think so. Most people have avoided the H3N2 type-A influenza strain that has been circulating since October. By the way, that’s early! Normally the flu doesn’t cause a lot of mischief until December. February can be brutal. Influenza season can last until April or May. The good news is that this year’s flu season peaked early and has been declining since mid-December.
We Predicted This Year’s Flu Season Would Be Short!
We track influenza in the southern hemisphere quite closely. That’s because flu season is always six months ahead in Australia and New Zealand. (January is a great time to visit those countries because it is their summer.) The H3N2 type-A strain of influenza increased sharply in Australia (aka Oz) in early May and peaked there in mid-June. That was two months earlier than usual.
Here is how the Australian public health authorities described this year’s flu season:
• “Activity – The 2022 influenza season began earlier compared to recent years. While influenza and influenza-like illness (ILI) activity levels were higher than average across all systems, it was a shorter season with a large peak of laboratory-confirmed influenza notifications in early June. Notifications substantially decreased in July and remained low until the end of the 2022 season.
• Severity – The clinical severity for the 2022 influenza season was considered low. In the reporting period, of the 225,332 notifications of laboratory-confirmed influenza, 308 influenza-associated deaths (0.14%) were notified to the National Notifiable Disease Surveillance System (NNDSS).
• Impact – Given the high level of influenza activity in the community, it is likely there was low to moderate impact on society during the reporting period.”
This year’s flu season in Australia began declining in June and pretty much petered out by September. There was no second wave of influenza.
How Well Did the Vaccine Work for This Year’s Flu Season in Oz?
The predominant influenza variant in Australia was H3N2 type-A. According to the 2022 Australian Influenza Surveillance Report (AISR):
• “Based on preliminary data, the 2022 influenza vaccine significantly reduced the risk of hospitalisation with influenza. Estimated vaccine effectiveness was 44%.”
That is about what we normally see in the United States.
We have been tracking vaccine effectiveness in the US since 2004. Here is a link to see how effective the typical flu vaccine is on average.
This Year’s Flu Season in the US:
There are still many cases of type A H3N2 influenza, but the incidence is dropping. Last week only 4% of the people who saw their doctors had an influenza-like illness.
Some years there is a second wave of flu caused by type B strains. Australian public health authorities did not report such a pattern this year.
How Well is the Influenza Vaccine Working for This Year’s Flu Season in the US?
It is too early to know how well the flu shots are working during the 2022-2023 flu season. We suspect that the 44% number from Australia is a good predictor of how well the shots are working here.
Has it been a bad flu year so far? Some people point out that (Time, Jan. 19, 2023):
“…it’s the most severe flu season since the start of the pandemic.”
That is not saying much. It turns out that since the COVID-19 outbreak, influenza has been at its lowest levels in recent memory. You may find my article on this subject worth a few minutes of your time:
What’s Your Experience During This Year’s Flu Season?
Did you catch the flu? Were you vaccinated? How bad was it? We would love to learn about your experience in the comment section below.