Table VII.
Evidence for and against vertical transmission - Inconsistencies in the timing and repetition of RT-PCR makes it difficult to come to an inference
| Study | 1st RT-PCR | Time done | 2nd RT-PCR | Time done | For vertical transmission | Against vertical transmission |
|---|---|---|---|---|---|---|
| Yu N et al | 1 pos | 36 hours | 1 neg | Within 2 week | CS, and baby was isolated for 14 days | Placenta and cord blood neg. Contamination- baby showed mild SOB Don’t know exactly when baby became negative |
| Zeng L et al | 1pos | Day 2&4 | 1 neg | Day 6 | Cs, isolation | Cord blood and amniotic fluid neg. Positive in <5 days |
| 1pos | Day 2&4 | 1 neg | Day 6 | Cs isolation | Cord blood and amniotic fluid neg. Positive in <5 days |
|
| 1pos | Day 2&4 | 1 neg | Day 7 | If vag fluid contamination- why amniotic fluid neg? | Cord blood and amniotic fluid neg. Prematurity complication. Vaginal fluid contamination(PPROM) Ex utero infec? |
|
| Wang S et al | 1 pos | 36 hrs | 1 neg | Day 15 | Long gap between 1st and 2nd RT-PCR- difficult to know if baby was positive within a week (5-7 days) | Placenta and cord blood neg Baby asymptomatic |
| Ferrazzi E et al | 2 pos | Day 1 | 2 pos | Day 3 | Vaginal fluid contamination Likely contamination. RT-PCR not repeated after 5 days. Babies were relatively asymptomatic. |
|
| 1 doubtful | Few hours after birth | 1 pos | Day 3 | -do- | ||
| Alzamora MC et al | 1 pos | 16 hrs | 1 pos | 48 hrs | CS Diabetes |
Baby positive <5 days. Had resp difficulty and needed ventilated but was premature at 33 weeks? Cause is prematurity. |
| Khan S et al | 2 pos | 24 hrs | Not tested | CS neonatal pneumonia |
Insufficient information- pos at 24 hours and not repeated. | |
| Nie R et al | 1 pos | 36 hrs | 1 neg | Day 4 | Neg at D4 Placenta cord blood neg Isolated for 16 days ?contamination |
|
| Carosso A et al | 1 pos | 0 hr | 1 neg | 37 hrs (on same swab) | Vaginal contamination highly likely as same swab neg after 37 hours. Possibly low titres... | |
| Hu X et al | 1 pos | 36 hr | Not tested | Positive >day 7 Isolation CS-?vertical |
Amniotic fluid pos ?ex-utero inf |
|
| Diaz SA et al | 1 neg | Day 67 | 1 pos | Day 8 | High likelihood of ex-utero infection from Mum- Mum BF till D6 when baby showed symptoms and was tested. | |
| Zamaniyan M et al | 1 neg | 0 hr | 1 pos | 24 hrs | Amniotic fluid positive. If it was amniotic fluid contamination-should have been positive at birth as well. Cord blood was negative so unlikely vertical transmission? infection exutero? |
|
| Yu N et al | 1 pos | 36 hours | 1 neg | Within 2 week | CS, and baby was isolated for 14 days | Placenta and cord blood neg. Contamination- baby showed mild SOB Don’t know exactly when baby became negative |
| Zeng L et al | 1pos | Day 2&4 | 1 neg | Day 6 | Cs, isolation | Cord blood and amniotic fluid neg. Positive in <5 days |
| 1pos | Day 2&4 | 1 neg | Day 6 | Cs isolation | Cord blood and amniotic fluid neg. Positive in <5 days |
|
| 1pos | Day 2&4 | 1 neg | Day 7 | If vag fluid contamination- why amniotic fluid neg? | Cord blood and amniotic fluid neg. Prematurity complication. Vaginal fluid contamination(PPROM) Ex utero infec? |
*CS-Caesarean section; **PPROM-Prelabour premature rupture of membranes