New COVID-19 cases - Weekly review: 25 - 31 January

During the week from25 to 31 January, the number of people testing positive for COVID-19 increased from 843 to 999 (+19%), while the number of their identified close contacts remained stable at 2,774 compared to 2,760 from the previous week (+0.5%).

The number of PCR tests performed during the week of 25 to 31 January has also increased from 44,417 to 51,337.

As of 31 January, the number of active infections was 2,185 (compared to 2,137 on 24.01), while the number of people healed increased from 47,027 to 47,964. During the week in question, there were 14 new deaths related to COVID-19, compared to 9 the previous week. The average age of the deceased is 86 years.

The average age of those diagnosed as COVID-19 positive decreased to 36.8 years. ​

In the hospitals, the situation was still relaxed, with 55 hospitalisations in normal care and 13 hospitalisations in intensive care of confirmed COVID patients for the week of 25 to 31 January, compared to 62, respectively 15, the previous week.

The two COVID-19 Consultation Centres (CCCs), located in Kirchberg and Esch-sur-Alzette, have recorded a total of 6,840 visits since their opening, including 359 visits for the week of 25 to 31 January, which is slightly higher than the previous week (283).

Positivity rate and incidence rate

For the reference period, the effective reproduction rate (R) increased from 1.05% to 1.10% and the positivity rate on all tests performed (prescriptions, Large Scale Testing) rose to 1.95% compared to 1.90% the previous week (average over the week). It should be noted that the positivity rate for tests carried out on prescription, i.e. for people with symptoms, is 5.19%, compared to 4.63% the previous week.

The 7-day incidence rate is 160 per 100,000 residents. Note that for the week of 18 January, the incidence rate was 135 cases per 100,000 residents over 7 days.

Compared to last week, the incidence rate rose in all age groups, with the most considerable increase in the 0-14 age group (+68%) and the 15-29 age group (+26%). ​ The 60-74 age group, continues to have an incidence rate which is almost two times lower then the incidence rate of the rest of the population.

Quarantine and isolation

For the week from 25 to 31 January, 1,820 people were in isolation (-1%) and 3,557 in quarantine (+43% compared to the previous week).

Contaminations

For the 999 new cases, the family circle remains by far the most frequent source of transmission of COVID-19 infections with 43%, followed by the education sector (8.6%) and the help and care sector (7%). The rate of contamination for which the source is not clearly attributable decreased to 29.4%.

During the week of 18 to 28 January 2021, a more granular study of the sources and channels of contamination was carried out by the Health Inspectorate as part of a pilot project, on the basis of a questionnaire covering the places frequented during the last 14 days by the infected person, the activities carried out during this period and the sanitary measures observed on this occasion. This questionnaire was used by the Contact Tracing team when making telephone contact with 584 positive cases.

The data obtained from this exercise is currently being evaluated. A preliminary statistical analysis allowed several observations to be made. ​

First of all, with regard to the place of infection. Thus, in cases where the positive person indicated that he or she knew the source person (about 50% of the cases), contact took place indoors for 74% of them, while for 24% of the cases the contact took place both indoors and outdoors. For only 2%, an exclusively outdoor contact has been indicated. As for the question of which places were frequented during the last 14 days before the positive test, home, work and shops for basic necessities (food...) were most often mentioned.

As for the duration of exposure, contacts were mostly of long duration (>2 hours) and ephemeral contact contamination (<15 minutes) was rare (4%).

With regard to the type of interaction in relation to the transmission channel, it is interesting to note that in more than 90% of the cases, the person questioned indicated that they spoke directly with their contact and in 87% of the cases, they ate or drank with their contact case.

Further statistical analysis of the data obtained in the pilot project is continuing, in particular with regard to the "adherence to health measures" component. Work is underway to integrate this questionnaire into the regular work of the Conatct Tracing.

The evolution of the variants

Since the British variant B.1.1.7. began circulating in Luxembourg on 19 December 2020, 791 samples have been sequenced by the National Health Laboratory (LNS). Among these samples, 47 variants B.1.1.7. were detected. As for the South African variant B.1.351, the sequencing of which started on 11 January 2021, 4 cases were detected, the last sequencing dating back to 22 January 2021.

It is important to note that these figures are not representative. Indeed, the LNS does not systematically have the metadata to situate the samples in time or in the context in which they were taken. Certain sequences have been targeted. For example, of the 93 samples sequenced during the week of January 18, more than 50% were sequenced at the request of the Health Inspectorate within the framework of Contact Tracing.

The Health Directorate and the National Health Laboratory are in the process of setting up the means required to have a representative sample of the general population based on samples from different regions and age categories with the help of medical analysis laboratories. The aim is to have a real time epidemiological surveillance system for variants by the end of February. In the meantime, it is not appropriate to extrapolate or estimate the prevalence of variants among the population from the sequencing data. In addition, since a delay of 7 to 10 days must be observed to obtain the sequencing results, the data is incomplete for the week of 25 to 31 January.

Vaccinations: update on the situation

For the week of 25 to 31 January, a total of 4,715 doses were administered. 4,279 people received a 1st dose and 439 received a 2nd dose.

Wastewater monitoring in Luxembourg as part of SARS-CoV-2 

The latest CORONASTEP report drawn up by the LIST (Luxembourg Institute of Science and Technology), indicates an average prevalence of the virus in waste water at national and regional level. For the week from 25 to 31 January, the slight downward trend continues at the national level.

All CORONASTEP reports are available on the LIST website: https://www.list.lu/en/covid-19/coronastep/.

Press release by the Ministry of Health and the Luxembourg Institute of Science and Technology (LIST)