Economy 18 January 2024, 2:31pm

Respiratory infections pick up in Hungary after customary end-year drop

Portfolio

The 2023/24 cold season started dramatically in Hungary, and the end of last year brought a deceptive relief. However, as it was expected, the dip linked to the holiday season has given way to an uptick in the number of infections by the second week of 2024.

A word about the gap in the charts

The National Public Health Centre (NNK) first skipped the report for the 51st week of 2023 between Christmas and New Year. Then it published data only for the 51st week, but nothing for the 52nd week. Last week, it 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 has caused 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 but its press department did not dignify us with an answer. Hence the gaps remain.

The marked decline even between the 51st week of 2023 and the 1st week of 2024, however, looked odd so we looked at the previous years, and found that the drop between these two weeks was the second largest since 2011/2012.

Data worsen as expected

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).

A dip for the holiday season was anticipated, and - as discussed above - further moderation on the first week was not a shocker, either. 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 number of people seeking medical help with influenza-like symptoms per 100,000 population was higher than currently only once in the past 12 cold seasons.

If you'd like to take a closer look, here you go:

On the 2nd week of 2024, a total of 176,400 people sought medical help with severe acute respiratory infection (SARI), of whom 24,800 (14.1%) had flu-like symptoms. The former figure marks a 15.7% increase and the latter a 15.3 growth over the 1st week. 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 2 of 2022/23, showing higher figures for this cold season both for the number of people that visited GPs with flu-like symptoms and of SARI "patients".

We can also compare the SARI and flu numbers for 100,000 inhabitants. Despite the relief observed between the 51st week of 2023 and the 1st week of 2024, 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 (221 in total on a national level last week, up from 92 a week ago but down from this season's high of 327 on the 50th week).

The number of samples tested on the 2nd week was much higher than on the 1st week, with the COVID-19 positivity rate all over the place - it is currently down at 13.6%, the lowest in this season yet. 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 2nd week, the Covid positivity rate continues to stand out.

There were 166 people in hospital with SARI on the 2nd week, versus 177 a week ago. 47% of them were treated with COVID-19, down from 55.4% 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.

At the same time, we cannot even estimate when this turnaround will take place this year. In fact, it would be a surprise it if occurred at all. Why? Well, take a look at the two graphs below! The share of coronavirus in all samples tested was about half than currently a year ago (15% vs. 30.5% currently), while the percentage of influenza in the samples is way lower now than in the second week of 2023 (3.3% vs. 13.7%).

For the sixth consecutive week in this flu season (or should we say Covid season?), however, people who 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 101 in total by the end of the 2nd week). Other pathogens identified between the 40th and 2nd week were SARS-CoV-2 (924), respiratory syncytial virus (RSV, 26), adenovirus (2), parainfluenza (4), human metapneumovirus (HMPV, 11, and rhinovirus (34).

62 (79.5%) of the 78 COVID-19 patients were aged 60 and over, which compares with 85 (86.7%) a week earlier. The number of people in hospital with coronavirus infection dropped 20% from 98 a week ago.

24.1% of those hospitalised with SARI were children aged 2 years or younger, while nearly 55% 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 166 people with SARI in hospital on the week under review, down from 177 a week earlier. 19 of them were in the ICU, which corresponds to a 11.4% ratio, which compare with 20 (11.3%) 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.