Coronavirus disease (COVID-19) technical guidance by WHO Household transmission investigation protocol | Page 16

2.5 Laboratory evaluations
COMMENT: Guidance on laboratory testing is subject to change, depending on the context of the
specific evolution of the epidemic.
Laboratory guidance for COVID-19 can be found on the WHO website (8). Several assays that detect
the novel coronaviruses have been recently developed and the protocols or standard operating
procedures can also be found on the WHO website (18).
2.5.1 Specimen collection
COMMENT: The following is intended to guide minimum specimen collection from confirmed cases
and their household contacts. It may be more useful to collect respiratory specimens from study
participants at more frequent intervals, to provide more detailed insight into the duration of
shedding and the serial interval.
2.5.1.1 Confirmed cases
All baseline respiratory and serum samples (as directed by specimen collection guidance in
Country X) should be collected from confirmed cases and their household contacts, including any
persons without symptoms who have been screened and found to be positive for COVID-19, as soon
as possible after laboratory confirmation. It is important to liaise with the relevant local public health
laboratory or the nearest relevant laboratory, to determine which specimens have already been
collected for confirmed cases and whether they are of sufficient quality and quantity for this
investigation. New samples should be collected if needed.
Follow-up samples (and other samples) may include upper respiratory tract samples and clotted
blood 1 , but also oral fluid, urine and faeces, and should be collected as described in Fig. 1. Lower
respiratory tract samples can also be collected, if feasible, but recommended infection prevention
and control precautions should be in place prior to collection (see Section 2.9.3), as these are
higher-risk interventions (19).
Other specimens (oral fluid, urine, faeces, etc.) may be collected according to clinical presentation,
resources and observed patterns of viral shedding (described earlier), and may be collected by
research staff, depending on resources, logistics and training.
Appropriate personal protective equipment (PPE) should be worn when specimens are being
collected from confirmed cases (19).
2.5.1.2 Household contacts
All baseline upper respiratory tract specimens (nasopharyngeal/oropharyngeal swab) and serum
samples should be collected at the initial home visit.
Respiratory specimens should be collected for molecular testing, as well as serum samples for
serology, from all members of the household, regardless of symptoms, together with the
administration of the baseline questionnaire. At the Day 7 and Day 14 visits, respiratory samples
(and other relevant specimens) should be collected from all members of the household, for
1
Adapted from reference (19).
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