Economy 14 December 2023, 1:17pm

Flu season worsens in Hungary, with epidemic curve flattening a bit

Portfolio

The number of Hungarians seeking medical help with severe acute respiratory infections (SARI), including influenza-like symptoms has risen further on the 49th week of 2023 (Dec 3-11) in Hungary, albeit less sharply than previously, data by the National Public Health Centre (NNK) showed on Thursday.

Key findings

The number of samples tested remains low, but is still more than three times higher than a year ago.
The coronavirus positivity rate has jumped after a slump a week ago, with over 72% of patients hospitalised with SARI treated with SARS-CoV-2 infection.
For the first time in the current flu season, a handful of people infected by influenza and respiratory syncytial virus (RSV) also needed hospital care.
The number of people hospitalised with SARI and those in intensive care dropped slightly from a week ago.

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 start of this year's flu season does not look promising at all on this particular chart, although the sharp rise flattened slightly on the 49th week.

On the 49th week, a total of 262,600 people sought medical help with severe acute respiratory infection (SARI), of whom 31,100 (11.8%) had flu-like symptoms. The former figure marks a 5.2% increase over the 48th week and the latter a 7.6% rise, which come come after way sharper rises of 18-45% from the 45th week. The dip in the columns came on the back of two short weeks, with public holidays on 1 Nov and 23 Oct., when fewer people went to the doctor, and the autumn break in schools also helped in this respect.

The graph below allows a comparison with weeks 40 to 49 of 2022, showing higher figures for this year for both the number of SARI "patients" and those that visited GPs with flu-like symptoms.

We can also compare the SARI and flu numbers for 100,000 inhabitants. These charts will say more when we have more than just a couple weeks of data, but - unlike up to the 46th week - they suggest that the flu season might be more severe in 2023/24 than in 2022/23.

We need to highlight that this year authorities perform way more tests than a year ago, even though the number of samples tested remains extremely low (317 in total on a national level last week, up by a hair from 310 a week earlier).

The number of samples tested on the 49th week was only a tad higher than on the 48th week, with the COVID-19 positivity rate up sharply. Testing is almost non-existent and we may draw only extremely cautious conclusions from these findings as regards the bigger picture on the current epidemiological situation. This is basically the only set of Covid data authorities provide besides weekly wastewater sampling results.

As regards all samples tested up to the 49th week, the Covid positivity rate continues to stand out.

As authorities have been publishing separate SARI and flu statistics only since 2022, a longer-term comparison is possible only for the number of people seeking medical help with influenza-like symptoms. This is basically a magnification of the first ten weeks of the flu season depicted on very first graph above.

There were 252 people in hospital with SARI on the 49th week, versus 266 a week earlier. Almost three quarters (72.2%) of them were treated with COVID-19, up slightly from 71.8% a week earlier. Coronavirus was the main pathogen found in samples early in the flu season last year too. Actually, the first time the share of flu viruses in samples was higher than the share of SARS-CoV-2 occurred only at the start of this year in the 2022/23 flu season.

For the first time in this flu season, however, people tested positive for influenza virus and RSV also had to be hospitalised. The 47th week was the first one in this cold season when one of the samples showed influenza infection (up at 17 in total by the end of the 49th week). Other pathogens identified between the 40th and 49th week were SARS-CoV-2 (607), respiratory syncytial virus (RSV, 4), adenovirus (1), parainfluenza (3), human metapneumovirus (HMPV, 5), and rhinovirus (24).

114 (62.6%) of the 182 COVID-19 patients were aged 60 and over, which compares with 147 (77.0%) a week ago. The other two metrics, i.e. people in hospital with Covid, and 60+ Covid patients, show a decline from the previous week, -5.7% and -22%, respectively.

22.2% of those hospitalised with SARI were children aged 2 years or younger, while more than half of them were aged 60 and over. The first figure marks an increase, the latter a decline from a week ago. There was an increase in the number of the former (green columns) and a drop in the latter group (orange columns).

Another important indicator of the severity of an epidemic is how many of those hospitalised end up in the intensive care unit (or in the morgue for that matter). The NNK does not reveal mortality stats, though.

As mentioned above, there were 252 people with SARI in hospital on the week under review, down from 266 a week earlier. 27 of them were in the ICU, which corresponds to a 10.7% ratio, up slightly from 10.5% a week earlier.

Finally, we have an age breakdown both for SARI and flu patients. Children up to the age of 14 are on top of the SARI age rankings in terms of numbers, while they are only on the 3rd spot in the flu rankings, behind those between 35 and 59 and the hardest-hit 15-34 age group. The right-hand charts show the share of people with SARI 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 SARI, 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.