Economy 11 January 2024, 4:15pm

Epidemiological data show rare sharp improvement in Hungary

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After an extremely bad start in the cold season, Hungary's latest epidemiological data showed a relatively unusual drop in the number of people that sought medical help with influenza-like symptoms. However, this is certainly just a temporary relief linked to the holiday season and the winter school break, and the number of infections (flu, Covid, RSV) is going to pick up.

"Funny" choice of data publication

The National Public Health Centre (NNK) has opted for an interesting release pattern. It first skipped the report for the 51st week of 2023 between Christmas and New Year. Then last week it published data only for the 51st week, but nothing for the 52nd week. Today, it has published its epidemiological report not only for the 52nd week of 2023 but also for the 1st week of 2024.

However, the report for the 52nd week was extremely concise, missing a host of key figures, including on the actual number of Hungarians turning to the doctor with severe acute respiratory infection, including flu-like symptoms, an age breakdown of those seeking medical help, incidence per 100,000 population, and hospital data altogether. This causes unwanted breaks in our time series and graphs. We have asked the NNK if we could have more than just two paragraphs for the 52nd week and will update this article if further data are received.

The (eerie) calm before the storm

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 looks dramatic on this particular chart. While we had no reason to believe that the epidemiological curve will magically flatten out, the sudden and sharp drop seemed peculiar at first.

We have already projected a dip for the holiday season, and that the figures for the 52nd week would show further moderation. Employees generally take their leave at the end of the year, there's the winter break in schools, and a heightened reluctance to go to the doctor "with a simple cold".

The marked decline, however, looked odd so we looked at the previous years, and found that the decline from the 51st week of 2023 to the 1st week of 2024 was the second largest since 2011/2012.

This time we give you a fuzzy-looking chart too, which shows data for a longer period, i.e. going back to the 2011/12 flu season. The red circle shows why we were not optimistic a week ago about what was likely to come, and we are still reluctant to forecast a lasting improvement despite the massive dip.

Here's a blow-up of the period in question:

On the 1st week of 2024, a total of 152,400 people sought medical help with severe acute respiratory infection (SARI), of whom 21,500 (14.1%) had flu-like symptoms. The former figure marks a 37.5% drop and the latter a 36.2% decrease over the 51st week, which come come after increases of 12.6% and 29.5%, respectively. Columns are missing for the NNK did not publish these figures for the 52nd week.

The graph below allows a comparison with weeks 40 to 1 of 2022/23, showing higher figures for this cold season for the number of people that visited GPs with flu-like symptoms, but the number of SARI "patients" is already slightly below the base period's print.

We can also compare the SARI and flu numbers for 100,000 inhabitants. Despite the relief observed over the past three weeks, chances are that the epidemic will 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 (92 in total on a national level last week, down from 290 a fortnight ago but up from 16 (!) a week earlier).

The number of samples tested on the 1st week was much lower than on the 51s week, with the COVID-19 positivity rate all over the place. 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. Looking at the numbers, however, it's a pretty safe bet that SARS-CoV-2 remains the key pathogen for the time being.

As regards all samples tested up to the 1st 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 177 people in hospital with SARI on the 1st week, versus 243 a fortnight ago. Over 55% of them were treated with COVID-19, down from 69% two weeks 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 fifth consecutive week 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 70 in total by the end of the 1st week). Other pathogens identified between the 40th and 1st week were SARS-CoV-2 (894), respiratory syncytial virus (RSV, 16), adenovirus (1), parainfluenza (4), human metapneumovirus (HMPV, 8), and rhinovirus (34).

85 (87.7%) of the 87 COVID-19 patients were aged 60 and over, which compares with 113 (67.3%) two weeks ago. The other two metrics, i.e. people in hospital with Covid, and 60+ Covid patients, show a decline from the 51st week.

26% of those hospitalised with SARI were children aged 2 years or younger, while nearly 60% of them were aged 60 and over.

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 177 people with SARI in hospital on the week under review, down from 243 two weeks earlier. 20 of them were in the ICU, which corresponds to a 11.3% ratio, down from 31 (12.8%) 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.