A fixed cohort of adults in rural Kimpese will be followed up every two months since they are assumed to be at above average risk of contracting COVID-19. Every two months these individuals will be interviewed with a focus on COVID-19 related symptoms and possible exposure to the disease and have their temperature recorded. A social mixing survey will also be carried out to assess human contact behaviour. The data generated will help inform mathematical modelling that can predict which proportion of the population per age group is likely to get infected once COVID-19 is introduced in this rural population, and the epidemic size if no intervention, as well as when targeted interventions are introduced. During the outbreak, physical distancing measures could be implemented. The monitoring of social contacts, again using a social-mixing survey, will contribute to the understanding of the impact of such measures in a rural context on transmission of SARS-CoV-2. The results from the seroprevalence over time, will be used to refine and validate the predictions from the modelling results, (re)calibrate the model where needed, and test hypotheses on transmission-dynamics of COVID-19. In case of an established epidemic of Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) in the Health Zone of Kimpese, the sero-surveillance will be extended from an assumed high risk cohort to a representative sample of the overall population. Moreover, support to the COVID-19 control measures will be provided by the study team. The national guidelines recommend household transmission investigation for the first 100 confirmed laboratory cases. During the household visit, information on symptoms and one serum sample will be requested of all household members of the index case. If household members are present with symptoms and fever, the COVID-19 outbreak team of Kimpese will provide diagnostic testing and medical care.
The sero-surveillance will start in a cohort of 800 adults (18-50y). In case of an
established outbreak, this sample will be extended to 800 pre-school children (0-5y), 800
schoolchildren (6-17y) and elderly (50+y). Human interactions will be quantified for the
rural context of Kimpese in four age categories, pre-school children (0-5y), schoolchildren
(6-17y), adults (18-50y) and elderly (50+). A sample of 300 persons in each age group will be
selected.
The study site will be the Health Demographic Surveillance System (HDSS) in the health
district of Kimpese, Kongo-Central province, DRC, managed Centre de Recherche en Santé de
Kimpese (CRSK). Each village, household and household member is listed in the HDSS database,
each household has been geo-referenced. The HDSS has enrolled a cohort of 60 000 inhabitants
in 11 rural health areas of the district. CRSK is the partner involved in the study and from
the core database the cohort population for the study will be selected using two stage
sampling. In stage one 20 villages will be randomly selected from the HDSS database using
population size as sampling weight. In stage two a random sample of 40 eligible individuals
will be drawn in each of the selected villages.
In the cohort, a blood sample will be collected for serology (sero-surveillance). When an
individual presents seroconversion, the household attack rate will be explored. Information
on symptoms and one serum sample of each household member, irrespective of age, will be
requested during the next follow-up visit. Any study subject reporting symptoms or presenting
with a fever, will be referred to the Institut Médical Evangélique (IME) hospital for
appropriate medical care.
A social mixing survey will be carried out to assess human contact behaviour, in an extended
cohort involving four age groups (0-5 years; 6-17 years; 18-50 years; >50 years old), sampled
from the overall population in rural Kimpese.
Biological: serological surveillance
serological surveillance, detection of antibodies (Total Ig and IgM) developed against SARS-CoV-2 in a population living in a rural area (Kimpese, DRC)
Inclusion Criteria:
In order to be eligible for the sero-survey, study participants must meet the following
criteria:
- Resident of the Kimpese HDSS demographic surveillance area
- Adults 18-50 years old
- When SARS-CoV-2 transmission is confirmed, all ages will be eligible to participate
- Willing and able to provide written informed consent
In order to be eligible for the social-mixing survey, study participants must meet the
following criteria:
- Resident of the Kimpese HDSS demographic surveillance area
- Willing and able to provide written informed consent
Exclusion Criteria:
- refusal to participation
Centre de Recherche en Santé de Kimpese
Kimpese, Congo, The Democratic Republic of the
Raquel Inocencio da Luz, PhD, Principal Investigator
Insitute of Tropical Medicine