Economy 21 March 2024, 10:28am

Influenza epidemic keeps petering out in Hungary

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The number of Hungarians seeking medical help with acute respiratory infection (ARI), including influenza-like symptoms has dropped further on the 11th week of 2024, in line with seasonality. Hospitalisation statistics also improved. Almost a third of those in hospital are treated with respiratory syncytial virus (RSV) infection and more than 80% of them are children aged 2 and younger.

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The flu season generally peaks between the 7th and 10th week of the year, but the highest figures can vary greatly from one year to another. The coronavirus pandemic, for instance, put a serious dent into the spread of the flu (see graph below).

The number of people seeking medical help with influenza-like symptoms per 100,000 population (272.2) was higher than currently only once in the past 12 cold seasons, in 2022/23.

For the 52nd week of 2023, the NNK published only a couple of figures, hence the gaps in the graphs.

On the 11th week of 2024, a total of 196,500 people sought medical help with acute respiratory infection (ARI), of whom 26,400 (13.4%) had flu-like symptoms. The former figure marks a 15.6% drop and the latter a 29.2% decline over the 10th week.

We can also compare the ARI and flu numbers for 100,000 inhabitants. The epidemic has been more severe in this respect in 2023/24 than in 2022/23 in about half of the weeks so far, between the 47th week of 2023 and the 7th week of 2024.

We need to note that this year authorities perform more tests than a year ago, even though the number of samples tested remains extremely low (229 in total on a national level last week, down from 309 a week ago).

The COVID-19 positivity rate dropped to just 0.4%, while the influenza positivity rate edged up to 13.1% after halving to 12.3% on the 10th week. The positivity rate for the respiratory syncytial virus (RSV), eased to 9.2% after rising to 10.4% a week earlier.

If we take a look at the positivity rates on the individual weeks, we find that there was a turnaround on the 2nd week, with the influenza positivity rate (14.0%) higher than the Covid positivity rate (13.6%) for the first time in the current flu season. The gap has widened considerably, reaching 38.8% percentage points on the 6th week and has since then come down to 11.0% on the 10th week, but widened to 12.7% on the 11th week.

The influenza positivity rate was certainly way higher a year ago, and the Covid positivity rate is also lower currently, while the RSV rate was lower a year ago.

As regards all samples tested up to the 11th week, the Covid positivity rate continues to be the highest, but the flu positivity rate is coming up and might eventually catch up. It has time to do so until the 20th week when the NNGYK stops publishing epidemiological data for this flu season.

The share of coronavirus in all samples tested (orange lines) was a lot smaller a year ago (10.4%) than currently (17.6%), while the percentage of influenza in the samples (green lines) is considerably lower now (16.0%) than in the period between the 40th week of 2022 and 11th week of 2023 (43.0%).

As regards the prevalence of respiratory syncytial virus (RSV) in the samples (blue lines), the situation is much better in the current cold season than in 2022/23, with the share only at 4.6% on the 11th week this year versus 10.8% a year ago. Note that these are the percentages of the select pathogens found in all samples tested up to the 11th week.

People tested positive for influenza and RSV had to be hospitalised for the 14th consecutive week in this flu season. The 47th week was the first one when one of the samples showed influenza infection (up at 971 in total by the end of the 11th week). Other pathogens identified between the 40th and 11th week were SARS-CoV-2 (1,065), respiratory syncytial virus (RSV, 278), adenovirus (6), parainfluenza (7), human metapneumovirus (HMPV, 102, and rhinovirus (50).

THERE WERE 162 PEOPLE IN HOSPITAL WITH SARI ON THE 11TH WEEK, VERSUS 262 A WEEK AGO AND THE PEAK AT 357 ON THE 8TH WEEK. 1.2% OF THEM WERE TREATED WITH COVID-19, DOWN FROM 2.3% A WEEK EARLIER, WHILE 12.3% OF THEM WERE TREATED WITH INFLUENZA, up slightly FROM 11.8% ON THE 10TH WEEK. THE SHARE OF RSV PATIENTS ROSE TO 32.1 from 29.0%.

The graphs below show a comparison with the previous 'flu season'. In 2022/23, there were no reports of people with Covid in hospitals up to the end of 2022, but that doesn't mean there weren't any (there were 100 on the first week of 2023, so it's a pretty safe bet that not all of them got to that stage overnight). In this respect, the Covid situation is now a lot better.

The following chart depicts the number and share of people infected by influenza virus who had to be hospitalised. As you can see (orange columns, light blue curve), this 'flu season' was worse in this respect than the previous one up to the 8th week, but we see a turnaround on the 9th week and a sharp drop on the 10th week with a further decline on the 11th week. The share of influenza patients of all people in hospital is way lower now (12.3%) than a year go (15.6%). (The chart starts on the 49th week because that was the first week in this season when someone infected with influenza virus had to be hospitalised.)

We have the same graph for respiratory syncytial virus (RSV), which shows that this infection was more severe in the previous 'flu season' up to the sixth week, but there was a turnaround on the 7th week. While the number of people treated with RSV in hospitals dropped moderately, their share as a percentage of all people hospitalised with SARI rose to 32.1% and remains way higher than a year ago (11.5%) when only 31 people with RSV were in hospital against 52 currently.

Another important indicator of the severity of an epidemic is how many of those hospitalised end up in the intensive care unit.

As mentioned above, there were 162 people with SARI in hospital on the week under review, down from 262 a week earlier. 17 of them were in the ICU, which corresponds to a 10.5% ratio, which figures compare with 39 and 14.9% a week earlier.

51.9% of those hospitalised with SARI were children aged 2 years or younger (down a tad from 52.7% two weeks ago which was the highest in this flu season yet), while 24.1% of them were aged 60 and over (up from 22.5 on the 10th week). For the sixth time in this flu season, both the number and share of children aged 2 years or younger in hospital with SARI came in higher than the corresponding figures for those 60 and over.

Half of those with ARI are children

Finally, we have an age breakdown both for ARI and flu patients. Children up to the age of 14 are on top of the ARI age rankings in terms of numbers, and for the ninth time this season they are also on top in the flu rankings, while the second hardest-hit cluster is the 15-34 age group. The right-hand charts show the share of people with ARI and flu-like symptoms by age group.

Looking back on the 2022/23 data we find that the 0-14 age group was the hardest hit throughout the flu season in terms of ARI, while in terms of flu-like symptoms they were the most affected age group between the 3rd and the 15th week of this year, i.e. from mid-January to mid-April.

On the 11th week this year, about 99,000 children sought medical help with ARI, 50.4% of all people that turned to the doctor with some respiratory infection. They also stand out when it comes to flu-like symptoms (42.4% of all), with their number down at 11,200 from over 15,500 a week ago.