More than 118,000 internal saliva tests in the university community during the COVID-19 crisis

Saliva testing at ULiège began on 28 September 2020. It was interrupted from 25 October 2020 (due to the return to distance learning - except for practical work and laboratories - and the return to compulsory teleworking) to 5 February 2021. It resumed on 8 February 2021 and did not stop (except for periods of leave at the university) until the end of June 2022.

During these 21 months, a total of 118,000 saliva tests were conducted within the university community.

• 40,582 tests performed by SARSSURV participants (figure as of week 23 - 2022)
• 77,485tests performed by the university community outside the SARSURV study (figure as of week 24 - 2022)

The positivity rate for all tests was 2.63%.

• 1.38% for tests performed within the framework of the SARSSURV survey
• 3.28% for tests performed outside the SARSSURV study

In the framework of the survey on compliance with barrier measures, more than 2950 missions were carried out by 70 student jobbers, during which nearly 250,000 behaviours were observed during the academic years 2020-2021 and 2021-2022. In the framework of the survey on the acceptability of barrier gestures, 1402 responses were obtained.

Two scientific publications have been produced: the first on the data on compliance with barrier measures collected during the first four months of the 2020-2021 academic year, and the second on the data on the acceptability of these barrier measures collected during the same period.

Furthermore, since the return to semi-presidential teaching in the second quarter of 2020-2021 and with the exception of holiday periods, data on compliance with the barrier measures has been provided to the ULiège Risk Assessment Group on a weekly basis.

A publication on the compliance data for the second quarter of the year 2020-2021 is currently being finalised, while two other publications will be written: one on the acceptability data collected later in the first quarter of 2020-2021, and the other on the compliance data collected during the academic year 2021-2022.

In addition, the method developed can be re-used in the future if necessary.

The barrier compliance survey would not have been possible without the work of the 70 student volunteers from all the faculties and campuses of the University of Liège and the help of Nicolas Ochelen from the administration of the Faculty of Veterinary Medicine in obtaining the necessary schedules for planning the missions.

As of 12 June 2022, 1266 participants are enrolled in the SARSSURV survey. Most of them are female staff (37.1%), followed by male staff (25.9%), female students (23.3%) and male students (13.7%). The vaccination rate of the participants in the SARSSURV study is 94.7% for a complete primary vaccination. 80.7% of the participants received a booster dose and 0.7% a 4th dose.

Since the beginning of the survey in April 2021, the investment of the participants who have participated or are still participating in the survey represents 40,582 saliva tests performed (of which 562 positive) and 5476 blood tests performed (figure as of week 23 - 2022).

Thanks to the results of the currently available blood self-tests, we are able to observe the evolution of the presence of antibodies against SARS-CoV-2 (seroprevalence) in the SARSSURV population. Namely, of the 913 participants with a known self-test result in the last three months, 92% reported SARS-CoV-2 antibody levels detectable by this method.

Analysis of the blood samples quantified the level of neutralising antibodies against SARS-CoV-2. According to the current results from the laboratory (analysis of samples up to 2 June 2022), 63.3% of the participants have developed sufficient neutralising antibodies and 30.7% very sufficient. On the other hand, 2.4% of the participants did not produce enough antibodies to neutralise the virus. Finally, 3.6% of the participants did not take a blood sample (not vaccinated, not infected). Based on the first available cellular immunity results (analysis of samples up to 8 June 2022) for 807 participants, 90.3% of participants have cellular immunity.

All these results will be the subject of several manuscripts currently being written. The study protocol has already been published.

Thanks to the involvement of the academic community, we have been able to build up a remarkable cohort that will help us answer different research questions that will allow us to better understand this pandemic. However, more than two years after the beginning of this crisis, it is still not over and its evolution is still uncertain.

In this context and in view of the current health situation, the SARSSURV survey has been extended until the end of December 2022, in a lighter and less restrictive version. Participants who wish to continue will be asked to take blood samples (2 samples) according to their profile (vaccination, infection). This will allow us to continue our research into the longer-term evolution of immunity to the virus. There will no longer be a weekly saliva test or a monthly blood self-test.

The SARSSURV survey mobilises a coordination team, a logistics team, a nursing staff, 5 analysis laboratories, a team of biostatisticians as well as numerous partners from the ULiège and the CHU of Liège. These teams are made up of a large number of researchers, computer specialists, nurses, laboratory managers and technicians, biostatisticians and jobbers.

The University of Liège is developing its air quality monitoring network by means of C02 sensors placed inside its premises, amphitheatres, classrooms, study rooms, etc.

The current system is being gradually increased and, by September 2022, some 250 sensors of various types will be operational in ULiège buildings on all campuses. All classrooms with at least 30 people will be equipped.

The campaign to prevent the epidemic by means of saliva testing was based on a mathematical model to describe the spread of the virus within the university community. The parameters of this model were identified on the basis of various observations of the health situation over time, in particular the number of people detected as positive, both in the university population and, more widely, in Wallonia. 

The use of the mathematical model for other sets of parameter values made it possible to simulate what the epidemic would have been like in other configurations. Among other things, the influence of saliva testing was evaluated and the model made it possible to determine the number of contaminations that were actually spared in the different waves that followed.

The model was also applied to saliva testing in nursing homes.

Three scientific articles have been published or are in the process of being published in renowned scientific journals.

Denoël, V., Bruyère, O., Louppe, G. et al. Decision-based interactive model to determine re-opening conditions of a large university campus in Belgium during the first COVID-19 wave. Arch Public Health 80, 71 (2022). https://doi.org/10.1186/s13690-022-00801-w 

M. Arnst, G. Louppe, R. Van Hulle, L. Gillet, F. Bureau, V. Denoël, A hybrid stochastic model and its Bayesian identification for infectious disease screening in a university campus with application to massive COVID-19 screening at the University of Liège, Mathematical Biosciences, Volume 347, 2022, 108805, ISSN 0025-5564, https://doi.org/10.1016/j.mbs.2022.108805 

This working group was able to recruit Romain Van Hulle, a research engineer who contributed to the development of the model, its adjustment and the analysis of its different variants.

A working group of the Risk Assessment Group was dedicated to the creation of an awareness-raising device in line with the objectives and challenges of the communication strategy adopted by the University of Liège concerning the development of COVID-19.

On this occasion, a "serious game" type management video game was created. Entitled ‘Sars Wars’ , the game consists of a crisis management simulation including epidemiological and health science data. The player must combat the development of a pandemic similar to COVID-19 in a compartmentalized susceptible-infected-recovered (SEIR) model adapted from research at ULiège (Saegerman et al, 2021 ; Denoël et al, 2022).

The creation of the game is the result of collaboration between the Risk Assessment Group, the GIGA, the RADIUS platform, the Liège Game Lab and the AR/VR laboratory at HEC Liège. Transdisciplinary teams participated in writing the game.

Two results should be highlighted. On the one hand, the structure of Sars Wars can be reused in other crisis management contexts. On the other hand, the game is now being used in the framework of quantitative research complementary to the SARSSURV seroprevalence study (Donneau et al., 2022).