Table 2.

Confirmation of Congenital ZIKV infection in the birth cohort, Nha Trang, Vietnam, July 2017–September 2018

			Gestational age (weeks/days)	Birth weight (g)	Head circumference (cm)	Maternal age (years)	IgM			Flavivirus IgG titer	Neutralization titer (50% focus reduction neutralization test)						ZIKV real-time reverse transcription–PCR (copies/mL)
Study year	No.	Gender					ZIKV	DENV	JEV		ZIKV	JEV	DENV-1	DENV-2	DENV-3	DENV-4	E gene primer	NS5 gene primer
2017	1	F	38/0	2,800	32.5	34	2	0.7	0.6	41,712	1,280	160	80	160	160	320	2.8 × 104	1.8 × 104
	2	M	38/2	3,000	34.5	34	3.3	0.7	0.1	8,518	640	< 80	< 80	80	< 80	< 80	UND	3.2 × 104
	3	M	39/3	3,400	33	38	3.7	0.8	0.3	29,541	640	80	160	160	160	< 80	4.1 × 104	2.1 × 104
	4	F	40/1	3,100	33	29	3.7	2.5	2.3	72,232	1,280	80	320	320	320	320	UND	6.5 × 104
	5	M	40/4	3,100	33.5	29	2	0.6	0.5	17,318	640	< 80	80	160	< 80	80	1.3 × 104	UND
	6	F	40/2	3,600	34.3	23	2	0.8	0.5	31,677	2,560	80	640	640	160	320	1.3 × 103	UND
	7	M	40/2	2,800	32	28	17.9	14.9	13.1	72,944	20,480	160	5,120	5,120	5,120	1,280	2.2 × 104	UND
	8	F	39/3	3,400	33.5	42	7.9	6	5.8	57,360	2,560	320	160	320	< 80	640	4.0 × 104	1.2 × 104
	9	F	39/2	3,100	33	21	8.6	2	0.6	10,320	1,280	160	320	160	160	320	1.6 × 104	3.5 × 104
2018	10	M	39/6	4,000	34.5	28	2	1.4	0.5	33,395	320	80	80	< 80	80	80	1.9 × 103	UND
	11	F	37/2	2,500	31.5	25	2.3	0.6	1.2	24,035	640	< 80	80	160	160	80	2.6 × 103	1.3 × 104

DENV = dengue virus; F = female; JEV = Japanese encephalitis virus; M = male; UND = undetermined; ZIKV = Zika virus; cutoff value of IgM P/N ratio = 2; cutoff value of IgG titer = 3,000.

ZIKV IgM and neutralization titers, which are diagnostically important, are shown in bold figures