Coronavirus disease (COVID-19) technical guidance: The Unity Studies: Early Investigation Protocols

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The Unity Studies: WHO Early Investigations Protocols

The emergence of a new virus means that understanding transmission patterns, immunity, severity, clinical unity studies_pic2features, and risk factors for infection are still limited. To address these unknowns, WHO has launched a global initiative which aims to enable any countries, in any resource setting, to gather rapidly robust data on key epidemiological parameters to understand, respond and control the COVID-19 pandemic. WHO, in collaboration with
technical partners, has developed several generic investigation protocols, branded the WHO Unity Studies. These protocols use a combination of molecular and serologic testing.

These protocols are designed to rapidly and systematically collect and share data in a format that facilitates aggregation, tabulation and analysis across different settings globally.

The widespread adoption of the Unity protocols in more than 90 countries, underlines their usefulness to support countries’ decision-making to implement or lift appropriate public health and social measures to prevent and control the COVID-19 infection.

 

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For more information or questions on the Unity global initiative, contact us:

EarlyInvestigations-2019-nCoV@who.int

Summary of protocols available for country use and adaptation:

Protocol and question to be answered / population under investigation: Objectives
Protocol:
Population-based age-stratified seroepidemiological investigation protocol for COVID-19 infection
 
Question/ population:
Virus infection in the general population 
 
Primary objectives:
  • To measure the seroprevalence of antibodies to COVID-19 in the general population by sex and age group, in order to ascertain the cumulative population immunity; and
  • To estimate the fraction of asymptomatic, pre-symptomatic or subclinical infections in the population and by sex and age group.
Secondary objectives, such as, but not limited to:
  • To determine risk factors for infection by comparing the exposures of infected and non-infected individuals;
  • To contribute to determine the case fatality ratio; and
  • To contribute to an improved understanding of antibody kinetics following COVID-19 infection.
Protocol:
The First Few COVID-19 X cases and contacts transmission investigation protocol (FFX)
 
Question/ population:
Cases and close contacts in the general population or can be restricted to semi-close settings (like households, health care settings, schools).

The primary objectives are to provide descriptions or estimates of :

  • clinical presentation of COVID-19 infection and course of associated disease;
  • secondary infection rate (SIR) and secondary clinical attack rate of COVID-19 infection among close contacts (overall, and by key factors such as setting, age and sex, for various end-points);
  • serial interval of COVID-19 infection;
  • symptomatic proportion of COVID-19 cases (through contact tracing and laboratory testing); and identification of possible routes of transmission.
  • identification of possible routes of transmission

The secondary objectives are to support the estimation of:

  • the basic reproduction number (R0) of COVID-19 virus;
  • the incubation period of COVID-19; and
  • the preliminary COVID-19 infection and disease-severity ratios (for example, case‑hospitalization ratio [CHR] and case-fatality ratio [CFR]).


Protocol:
Household transmission of COVID-19 investigation protocol (HH)
 
Question/ population: Cases and close contacts in household setting

Primary objectives:

  • To better understand the extent of transmission within a household by estimating the secondary infection rate for household contacts at an individual level, and factors associated with any variation in the secondary infection risk.
  • To characterize secondary cases including the range of clinical presentation, risk factors for infection, and the extent and fraction of asymptomatic infections
  • To characterize serologic response following confirmed COVID-19 infection
Assessment of COVID-19 risk factors among Health Workers (HW)
 
 
 
 

Protocol:
Prospective study of a cohort of health workers)
 
Question/ population:
All health workers in a health care setting in which patient(s) with a laboratory-confirmed COVID-19 infection are receiving care

 

 

 

 

 

 

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Protocol: 
Protocol for a case-control study
 
Question/ population:
Health workers exposed to COVID-19 patients 
 

Primary objectives:

  • To better understand the extent of human-to-human transmission among health workers by estimating the secondary infection rate[1] for health worker contacts at the individual level.
  • To characterize the range of clinical presentations of infection and the risk factors for infection among health workers.
  • To evaluate the effectiveness of infection prevention and control measuresamong health workers.
  • To evaluate the effectiveness of infection prevention and control programmes at health facility and national level.

Secondary objectives such as, but not limited to:

  • To determine the serological response of health workers with symptomatic and possibly asymptomatic COVID-19 infection;
  • To characterize the duration and severity of COVID-19-associated disease among health workers.

 

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The primary objective of this case-control study among health workers is:
  • to characterize and assess the risk factors for SARS-CoV-2 infection in health workers exposed to COVID-19 patients.
The secondary objectives of the study are:
  • to evaluate the effectiveness of current COVID-19 IPC measures among health workers;
  • to describe the range of clinical presentation for SARS-CoV-2 infection in health workers, including disease duration and outcome; and
  • to determine serological responses in health workers with confirmed SARS-CoV-2 infection following exposure to COVID-19 patients, and in those exposed to COVID-19 patients but without SARS-CoV-2 infection.

 

Protocol:
Schools and other educational institutions transmission investigation protocol for COVID-19
 
Question/ population:
Students and staff of schools and other educational institutions with a laboratory confirmed case of COVID-19
 
 

The overall aim is to gain an understanding of the transmission dynamics of COVID-19 infection among cases and contacts within schools and other educational institutions.
Primary objectives are:

  • to estimate infection rates for overall and secondary COVID-19 infections in this context
  • to estimate the secondary clinical attack rate of COVID-19 in this setting
  • to estimate the fraction of asymptomatic COVID-19 infections within schools and other educational institutions
  • to describe the epidemiological and clinical characteristics of primary and secondary cases of COVID-19
  • to identify potential risk/protective factors associated with the COVID-19 infection risk.

Secondary objectives are:

  • to estimate the incubation period of COVID-19 and the duration of infectiousness and of detectable shedding;
  • to estimate the serial interval of COVID-19 infection in this setting;
  • to estimate the reproduction numbers: R0 and R of COVID-19 in this setting; and
    to characterize the serological response following confirmed COVID-19 infection
Protocol:
Surface sampling of COVID-19 virus: A practical “how to” protocol for health care and public health professionals
 
Question/ population :
For environmental surfaces 
Primary objectives:
  • To assess the extent and persistence of surface contamination of COVID-19; and
  • To identify environmental surfaces and fomites that may play a role in onward transmission of COVID-19.
Secondary objectives such as, but not limited to:
  • To characterize of the sequence diversity of COVID-19 in environmental samples, as capacity and resources permit.

For more information, please contact: EarlyInvestigations-2019-nCoV@who.int


List and access to individual protocols:

1 -  Population-based age-stratified seroepidemiological investigation protocol for COVID-19 virus infection

Access the protocol

This protocol is a population-based, age-stratified prospective study for assessing COVID-19 virus infection. It is intended to provide key epidemiological and serologic characteristics of COVID-19 virus in the general population. This includes the extent of infection in the general population and age-specific infection cumulative incidence, as determined by seropositivity, and the fraction of asymptomatic or subclinical infection

 

 

2 -  The First Few X (FFX) Cases and contact investigation protocol for COVID-19 infection

Access the investigation protocol 

The following protocol has been designed to investigate the First Few X number of cases and their close contacts (FFX).  It is envisioned that the FFX -COVID-19 investigation will be conducted across several countries or sites with geographical and demographical diversity. Using a standardized protocol such as the protocol provided here, epidemiological exposure data and biological samples can be systematically collected and shared rapidly in a format that can be easily aggregated, tabulated and analyzed across many different settings globally for timely estimates of COVID-19 infection . FFX is the primary investigation protocol to be initiated upon identification of the initial laboratory-confirmed cases of COVID-19 in a country.

For a more targeted approach on specific groups and more precise estimation of epidemiological parameters, two other investigation protocols are available:

 

3 -  Household transmission investigation protocol for COVID-19 infection

- Access the investigation protocol 

The household transmission investigation is a case-ascertained prospective study of all identified household contacts of a laboratory confirmed COVID-19 infection. It is intended to provide rapid and early information on the clinical, epidemiological and virological characteristics of COVID-19. 

 

4 -  Assessment of risk factors for COVID-19 in health workers: protocol for a prospective study of a cohort of Health worker

Protocol for a prospective study of a cohort of HW 

- Access the protocol

The extent of COVID-19 infection in health care settings is not clear, nor whether there are certain risk factors associated with infection in health care workers. The following protocol has been designed to investigate the extent of infection and risk factors for infection among health care workers. Follow-up and testing of respiratory specimens and serum of health care workers within a facility in which a confirmed case of COVID-19 infection is receiving care can provide useful information on transmissibility and routes of transmission and are important for limiting amplification events in health care facilities.

Protocol for a case-control study

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Aiming at assessing risk factors for COVID-19 in health workers, the current protocol consists of a nested case-control study of health workers involved in the care of any confirmed COVID-19 cases. The study is based upon the use of incidence density sampling. The study is to be initiated as soon as a case of SARS-CoV-2 infection is confirmed among health workers in a health care setting. Health workers with confirmed COVID-19 will be recruited as cases. Health workers exposed to COVID-19 patients in the same setting but without infection will be recruited as controls with a target of at least 2–4 controls for every case.

For countries or health care facilities willing and able to participate, WHO is proposing to conduct an international multi-centre case-control study. For more information, please contact: EarlyInvestigations-2019-nCoV@who.int. Upon request, WHO will provide a Go.Data template for data collection to local investigators.

 

5- Schools and other educational institutions transmission investigation protocol for coronavirus disease 2019 (COVID-19)

- Access the protocol

The overall aim of this protocol is to gain an understanding of the transmission dynamics of COVID-19 infection among cases and contacts within schools and other educational institutions.

 

6 - Surface sampling of coronavirus disease COVID-19 virus: A practical “how to” protocol for health care and public health professionals

- Access the protocol

The role of environmental contamination in transmission of COVID-19 virus is currently not clear. This protocol has been designed to determine (viable) virus presence and persistence on fomites in various locations where a patient infected with COVID-19 is currently receiving care or being isolated, and to understand how this may relate to COVID-19 transmission events in these settings. It is therefore important that it is done as part of a comprehensive outbreak investigation and that information obtained by environmental studies is combined with the results of epidemiological, laboratory and sequence data from COVID-19 patient investigations.

For more information, please contact: EarlyInvestigations-2019-nCoV@who.int.