Coronavirus disease (COVID-19) technical guidance by WHO Investigation protocol for COVID-19 | Page 7

may be used can be found in the Appendix A. This questionnaire is not exhaustive and may need to
be adapted to the local setting and outbreak characteristics, but it provides an outline as to the data
to be collected in order to calculate the epidemiological parameters (see 4.3 Epidemiological
parameters).
2.5 Specimen collection
A serum sample needs to be collected from each participant upon recruitment into the investigation.
The collection of serum samples should follow specimen collection guidance in the country.
Table 1 describes when data and specimens should be collected according to the study design
selected. If repeated sampling is to be conducted, whether as a repeated cross-sectional
investigation, or as a longitudinal investigation, specimens should be collected at least 21 days apart.
COMMENT: Other specimens (e.g. nasopharyngeal) may be collected to determine acute COVID-19
infection, as determined by the objectives of the investigation and the available resources and
capacity.
Figure 1: Schedule for data and specimen collection according to study design
Study design Baseline
Cross-sectional
investigation Data and
specimen
collection
Repeated cross-
sectional
investigation Data and
specimen
collection
Longitudinal
cohort
investigation Data and
specimen
collection
Further
recruitment
and follow-up
(at least 21
days after
baseline)
Regular follow-up of same individuals recruited
(at least 21 days apart)
Data and
specimen
collection
Data and
specimen
collection
Data and
specimen
collection
Data and
specimen
collection
2.6 Specimen transport
All those involved in the collection and transportation of specimens should be trained in safe
handling practices and spill decontamination procedures. For details regarding the transport of
samples collected and infection control advice, please refer to case management algorithm and
laboratory guidance in the country or WHO laboratory guidance, available on the WHO website.
For each biological sample collected, the time of collection, the conditions for transportation and the
time of arrival at the study laboratory will be recorded. Specimens should reach the laboratory as
soon as possible after collection. If the specimen is not likely to reach the laboratory within 72 hours,
specimens should be frozen, preferably at -80°C, and shipped on dry ice. It is, however, important to
avoid repeated freezing and thawing of specimens. The storage of serum specimens in domestic
frost-free freezers should be avoided, owing to their wide temperature fluctuations. Serum should
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