COVID-19

Please note that there are different definitions and guidelines available to describe long COVID. Based on the definition used, the results may be different.
The COVIMPACT study in Sciensano was developed based on the definition of the National Institute of Health and Care Excellence (NICE): "symptoms persist or develop for more than 3 months after a COVID-19 infection and cannot be explained by another diagnosis” [1].

1. Key messages

2. Epidemiology of COVID-19

The coronavirus disease 2019 (COVID-19) pandemic started in December 2019 in the city of Wuhan, China. COVID-19 is caused by the virus SARS-CoV-2 (severe acute respiratory syndrome coronavirus 2). On 11 March 2020, the Director-General of the World Health Organization declared COVID-19 a global pandemic.

The virus is transmitted from human to human by infectious droplets. People can remain asymptomatic or present with a broad spectrum of symptoms. The risk of severe disease increases markedly with age and previous underlying conditions. For the general public, vaccination, handwashing, social distancing, avoiding crowded indoor spaces, and wearing a face mask are the recommended measures to protect oneself. Vaccines are available in Belgium since January 2021; more information on vaccines can be found here.

An overview of the scientific information about COVID-19 based on updated literature monitoring is available in the Sciensano fact sheet.

In Belgium, COVID-19 is monitored by Sciensano

In Belgium, the first confirmed case was reported on 3 February 2020, in an asymptomatic person repatriated from Wuhan. The second case was registered almost one month later, on 1 March 2020. This case was followed by a rapid growth in the number of cases occurring after the Carnival holidays. Since then, the virus is widely spreading in the country.

The Belgian institute for health, Sciensano, monitors the epidemic based on the data collected by its surveillance networks and reports on the latest figures and trends.

Four key indicators are followed; for the three first ones a moving average is computed on the last 7 days and compared to the average of the 7 previous days:

• the number of confirmed cases;
• the number of new hospitalizations of laboratory-confirmed cases;
• the number of deaths;
• the number of ICU beds occupied.

Moreover, the reproduction rate, that is the average number of people infected by a person carrying the virus, is calculated. If the reproduction rate is over 1, the disease is spreading in the population. Additional indicators are followed as the number of occupied beds in hospitals and ICU, vaccination coverage, the number of tests performed, and the percentage of those that are positive (positivity rate).

More information on COVID-19 mortality can be found on the following pages: ad-hoc surveillance of COVID-19 mortality 2020-2022, causes of death, causes of premature death.

Information on COVID-19 is available on different pages

Since the data are in constant evolution, this sheet refers to the main web pages where figures are updated regularly. Data can be consulted in several places and in several forms:

• Dynamic dashboard (updated every Friday).
• Reports:
  • The weekly Epidemiological Bulletin on Acute respiratory infections presents a summary of the main indicators.
  • Thematic reports with in-depth analyses of specific topics are available.
  • The clinical hospital surveillance report provides more information about hospitalized patients and patients in intensive care.
  • The wastewater surveillance report provides complementary information on the circulation of COVID-19.
• Open data are available.
• Frequently asked questions related to the different COVID-19 surveillance, data collection, and ways of reporting are answered in a specific document.

International data on COVID-19 can be consulted on different platforms

Comparisons among countries should be interpreted with caution due to differences in testing strategy, in laboratory capacities, and in the effectiveness of the surveillance. Comparisons of COVID-19 deaths are also hampered by differences in the methodology of counting COVID-19 deaths.

Epidemiological International data can be consulted on several platforms:

• European Centre for Disease Prevention and Control.
• World Health Organization.
• Johns Hopkins University: coronavirus resource center.
• Our world in data.

3. The proportion of long COVID

In the COVIMPACT study, the overall occurrence of long COVID was 47% three months after a SARS-CoV-2 infection, and 32% after 6 months. These numbers are in line with the international literature, which reports a prevalence of 47% and 30% for long COVID at 3 and 6 months [3].

All age groups are affected by long COVID

Although the proportion of long COVID differs slightly according to age, it is not a significant risk factor. Among participants with an age between 18 and 25 years, 47% reported persistent symptoms 3 months after a SARS-Cov-2 infection. This is similar to participants aged between 26 and 45 years where 51% reported persistent symptoms, but higher compared to the other age categories 46-65 years (42%) and 66+ (36%). At 6 months, the prevalence of long COVID has decreased among all age categories to 27%, 26%, 37%, and 21% respectively [3].

Women are more likely to report long COVID

In the COVIMPACT study, 37% of the participants were men and 63% of them were women. The proportion of long COVID at 3 months is higher amongst women (56%) in comparison to men (42%). After 6 months, the proportion decreased in women to 40% and men to 27%. Women are 1.4 times more likely to have long COVID than men at 3 and 6 months.

Participants with lower socioeconomic status are more vulnerable to long-COVID symptoms

Among participants with a lower educational status, 56% reported persistent symptoms 3 months after infection, which is slightly higher compared to patients with a higher educational level (47%). After 6 months, these proportions decrease to respectively 41% and 32%.

The most prevalent symptoms of long COVID are fatigue and exhaustion

The most prevalent symptoms reported by participants with long COVID at 3 and 6 months post-infection are fatigue and exhaustion (49% and 50%), headache (27% and 32%), memory problems (26% and 32%), respiratory problems (21% and 27%), sleeping problems (19% and 22%), loss of smell (20% and 17%) and taste (14% and 13%).

Patients with long COVID report a reduced quality of life

The health-related quality of life has been assessed with the EQ-5D questionnaire, which contains questions on mobility, autonomy, daily activities, pain/discomfort, and anxiety/depression. After 3 months, 18% of participants with long COVID reported mobility problems, 4% autonomy problems, 30% had problems with daily activities, 48% had pain and 40% of them reported anxiety and depression. After 6 months, these proportions were respectively 21% (mobility), 5% (autonomy), 33% (daily activities), 56% (pain), and 49% (anxiety and depression).

The mean score of health-related quality of life was assessed among COVIMPACT participants before their SARS-CoV-2 infection, at the time of infection, and after 3 and 6 months. Before infection, the average quality of life score was 92.6/100 and it significantly decreased at the time of infection to 81.7/100. For the scores 3 and 6 months after infection, a comparison was made between people who recovered from their infection and those who had long COVID. People who recovered from the infection had a higher quality of life score 3 and 6 months after infection (95.7/100 and 95.8/100) than people with long COVID (86/100 and 83.6/100).

4. Read more

View the metadata for this indicator

Would you like more information about COVID-19?

Besides his mission of surveillance, Sciensano is also involved in scientific research projects on COVID-19. In collaboration with partners, Sciensano coordinates and participates in projects aiming to better understand the virus and its effects on population health. Here is an overview of the existing projects.

Specific aspects of COVID-19 monitoring, prevention, and control are competencies of the regions. Further information on these aspects is available via the following websites:

• Zorg and Gezondheid
• AViQ
• Iriscare

We invite you to consult the following links: latest news, current measures taken by the Belgian government, guidelines to follow when COVID-19 symptoms appear.

If you are a professional, you can find the procedures for managing COVID cases on the Sciensano website.

Context

In Belgium and worldwide, at the beginning of the COVID-19 pandemic, the focus was on managing the acute phase of the disease. However, some people continue to experience symptoms beyond the acute phase of infection [4] [5]. This phenomenon is referred to as "long COVID" or "Post COVID-19 condition" [6].

There is currently no consensus on the definition of long COVID. Still, many studies apply the definition proposed by the National Institute of Health and Care Excellence: "symptoms persist or develop for more than 3 months after a COVID-19 infection and cannot be explained by another diagnosis [1].

In the COVIMPACT study, the two definitions used to describe long COVID 3 and 6 months after acute infection are (1) having at least one symptom related to the SARS-CoV-2 infection three months after it, (2) still have at least one persistent symptom related to the SARS-CoV-2 infection six months after it. The objective of the COVIMPACT project is to constitute a cohort of people who test positive for COVID-19 in order to:

• study the long-term evolution of a SARS-CoV-2 infection on physical, mental, and social health
• identify the groups at risk and the factors associated with a favorable/unfavorable evolution

COVIMPACT is a prospective online observational cohort study. The target group is people who have had a COVID-19 infection confirmed by a laboratory test. When a COVID-19 test is positive, the lab sends the information to a central database that is used by call centers to contact COVID-19 cases and trace their contacts. At the end of the call, the call center agents inform people aged 18 and over about our online survey and ask if they agree to receive a link by SMS for more information on the study, and potentially participate in the study and complete the first questionnaire. Follow-up questionnaires are sent by Sciensano every 3 months until the end of the study in April 2023. Depending on when participants entered the study, the follow-up varies from 3 months to 2 years. Between 29 April 2021 and 1 May 2022, 2092 people completed the first questionnaire and the two follow-up questionnaires (3 and 6 months after infection). Full details on the sample and design are described in the latest COVIMPACT study report. The following topics were assessed in the study: COVID-19, quality of life, breathing difficulties, fatigue, functional limitations, mental health, physical activity, employment, and economic status.

All these results can be found on the COVIMPACT website.

Definitions

SARS-Cov-2 infection

A confirmed case is defined as a person who has a confirmed diagnosis by molecular or antigenic test of COVID-19.

Long COVID

The COVIMPACT study in Sciensano was developed based on the definition of the National Institute of Health and Care Excellence (NICE): "symptoms persist or develop for more than 3 months after a COVID-19 infection and cannot be explained by another diagnosis”.

Moving average

The moving average is calculated as the average number of deaths across the last 7 days. The reason to use the moving average is that it smooths the daily fluctuations, and therefore, allows for a more robust appreciation of trends than the number of deaths that occurred during the last day.

Reproduction rate

The average number of people infected by a person carrying the virus. If the reproduction rate is higher than 1, the disease is spreading in the population.

Positivity rate

The positivity rate is the percentage of all COVID-19 tests performed that are positive.

References

1. National Institute for Health and Care Excellence,(NICE). (2020). COVID-19 rapid guideline: Managing COVID-19. NICE. https://www.nice.org.uk/guidance/ng191
2. Sciensano.(2020). COVID-19—Définition de cas et testing | Coronavirus Covid-19. https://covid-19.sciensano.be/fr/covid-19-definition-de-cas-et-testing
3. Smith P, Charafeddine R, Drieskens S, De Pauw R, De Ridder K, Demarest S, Van Cauteren D. Etude COVIMPACT : Infection COVID-19 et ses implications physiques, mentales et sociales à long terme – Résultats du suivi à 3 et 6 mois suivant l’infection. Bruxelles, Belgique. Juin 2022. Numéro de dépôt : D/2022.14.440/36 DOI : /10.25608/gyzc-w673
4. Amdal, C. D., Pe, M., Falk, R. S., Piccinin, C., Bottomley, A., Arraras, J. I., Darlington, A. S., Hofsø, K., Holzner, B., Jørgensen, N. M. H., Kulis, D., Rimehaug, S. A., Singer, S., Taylor, K., Wheelwright, S., & Bjordal, K. (2021). Health-related quality of life issues, including symptoms, in patients with active COVID-19 or post COVID-19; a systematic literature review. Quality of Life Research. https://doi.org/10.1007/s11136-021-02908-z
5. Taquet, M., Dercon, Q., Luciano, S., Geddes, J. R., Husain, M., & Harrison, P. J. (2021). Incidence, co-occurrence, and evolution of long-COVID features : A 6-month retrospective cohort study of 273,618 survivors of COVID-19. PLOS Medicine, 18(9), e1003773. https://doi.org/10.1371/journal.pmed.100377
6. World Health Organization, WHO. (2021). A clinical case definition of post-COVID condition by a Delphi consensus. https://apps.who.int/iris/handle/10665/345824

Please cite this page as: Sciensano. Communicable Diseases: COVID-19, Health Status Report, 26 Oct 2022, Brussels, Belgium, https://www.healthybelgium.be/en/health-status/communicable-diseases/covid-19