RESULTS
A total of 22 articles were shortlisted for addition into the final
manuscript. The PRISMA flow diagram of study selection at all stages can
be visualized in Figure 1. Two of the full texts were excluded due to
wrong population: discussing Middle Eastern Respiratory Syndrome (MERS)
and eight articles were excluded because they were either editorials or
commentaries.
The accepted articles can be visualized in Table 1 below. NOS measures
the risk bias and quality of the cohort and case control manuscripts on
bases of three variables: selection (scored out of 4 stars, represented
in the first row of table), comparability (scored out of 2 stars,
represented in the second row of the table) and exposure (measured out
of 3 stars, represented in the third row of the table). A score of 7 or
more is expected to be a good score. MQC measures the quality of
methodology using selection (scored out of one plus sign), ascertainment
(scored out of 2 plus signs), causality (scored out of 4 plus signs),
and reporting (scored out of 1 plus sign). A score of 6 or more was
considered a good score. AMSTAR score was used in reviewing the
methodology of included systematic reviews. AMSTAR marks on 11
components with yes, partial yes and no. To make the evaluation brief,
these three scores are grouped together and the final score is given in
the table. The guidelines were not evaluated because of the exhaustive
process and time constraints. Perspective reports and technical
documents were subjectively screened for risk bias assessment.
The demographics of patients in terms of trimester of pregnancy in which
diagnosis is made, the geographical location of patient(s) and symptoms
warranting screening and testing are included in the studies are shown
in Table 2 . A total of 403 pregnancies were considered in the study
with most of the patients in the third trimester of pregnancy. Due to
high volumes of data from China, most of the studies either originates
from mainland China or are published by Chinese authors. In the cohort
sampled, there was no maternal mortality reported and only 6 different
fetal mortalities have been reported by Schwartz et al, Zaigham et al,
Panah et al and Mullins et al. of which there was 1 intrauterine, 1
still birth and the other 4 neonates expired shortly after birth14-17.