Healthcare UTilisation and Seroprevalence Survey – Findings & Results

Epicentre News • 1July 2020

Over the past few months, we studied how COVID is impacting South Africans! HUTS is a Healthcare UTilisation and Seroprevalence Survey that aimed to find out more about the effect of the COVID-19 pandemic in South Africa.

The study was conducted by Genesis Analytics and Epicentre with the National Institute for Communicable Diseases (NICD).

Principle and role of our serological tests used in this study to measure COVID-19

A serologic test can determine whether a person has been exposed to a particular microorganism.

SARS-CoV-2 infection detects the development of antibodies 2 to 3 weeks after illness onset

The findings of the study provided useful insights on a population level for monitoring and responding to the COVID-19 pandemic

  • Proportion of a population previously infected with SARS-CoV-2
  • Identify which communities have been most affected
  • Guide public health response and control measures (NPIs and vaccines)
  • Identify levels of testing (infection-case ratio)

The HUTS study was not designed to provide details on individual decision-making. Further, studies will be conducted to:

  • Understand to what degree and for how long individuals with antibodies are protected
  • Understand what concentration of antibodies are needed to provide protection

Study Design and Population

Cross-sectional community survey was conducted in three communities where severe respiratory illness (SRI) and influenza-like illness (ILI) surveillance is conducted.

  • Klerksdorp (North West)
  • Pietermaritzburg (KwaZulu-Natal)
  • Mitchell’s Plain (Western Cape)

To ensure the validity and reliability of our findings, households were identified using randomly selected GPS coordinates within the selected areas.

Data Collection

  • Field workers collected data from primary caregivers as the representative of each household.
    • All selected households were asked to be included in the Healthcare Utilisation study.
  • Data was collected electronically using the Research Electronic Data Capture (REDCap, Vanderbilt University, USA) app on tablets.
    • Epicentre Health Research holds over 20 years of experience in electronic data capturing and choose to make the big move from paper, as it provides lightening fast results and increases reliability.

Laboratory Testing

  • Serum samples were tested using Wantai SARS-CoV-2 Ab ELISA (RBD of spike protein) and Roche Elecsys anti-SARS-CoV-2 ELISA (nucelocapsid protein) kits
  • Plasma samples were collected for HIV and viral load testing

Statistical Analysis

  • Participants were considered to have had a previous infection if positive on ≥1 ELISA assay
  • Seroprevalence = number positive for SARS-CoV-2 antibodies / total number tested
  • Mixed effects logistic regression was used as a control for clustering by site and household

Household characteristics stratified by site

HUTS: November 2020 – April 2021

Individual characteristics stratified by site, HUTS: November 2020 – April 2021

Underlying illness included asthma, diabetes, chronic heart disease, chronic lung disease, hypertension and cancer.

SARS-CoV-2 seroprevalence by site
HUTS: November 2020 – April 2021

SARS-CoV-2 seroprevalence by month, HUTS: November 2020 – April 2021



Mitchell’s Plain

Univariate analysis of factors associated with SARS-CoV-2 seropositivity.

HUTS: November 2020 – April 2021


Overall seroprevalence: 45%

Differed by site:

  • 40% Klerksdorp
  • 46% Mitchell’s Plain,
  • 49% in Pietermaritzburg

• Increased from 13% in Nov 2020 to 47% in Apr 2021

Highest seroprevalence:

  • 13-18 year (50%)
  • 19-24 year (54%)
  • 25-39 year (49%) age groups

No difference by HIV status

• Higher seroprevalence associated with higher BMI and lower SES

The results from our HUTS study reflected similar findings to other seroprevalence studies during/after second wave in SA:


  • residual blood from blood donors in Jan 2021
  • Number of participants – 4858
  • NC 32%, FS 46%, KZN 52%, EC 63%

PHIRST-C household cohort study

  • Conducted in March 2021
  • Number of participants – 1052
  • MP 26%, NW 41%

Our Key Partners

We thank our stakeholders and partners of the HUTS study for their support.

These include:

  • The participants who have agreed to be part of the study.
  • Department of Health and district counsellors for supporting this research.
  • Amelia Buys, Nokuthula Linda and Cayla Reddy of the Centre for Respiratory Diseases and Meningitis, NICD
  • Adrian Puren, Beverley Singh, and Zinhle Brukwe of Centre for HIV and STI, NICD
  • The PHRU Klerksdorp team who have supported our work in the area
  • The Epicentre data and field work teams