Abstract: Background：Children's Hospital of Fudan University was the designated hospital for newborns in the SARSCoV2 omicron variant wave in Shanghai from March to May 2022. Facing the complexity of the current pandemic, it was a challenge for special populations such as newborns to coordinate pandemic control and medical treatment. Objective：To implement and improve the bubble strategy for newborns on the basis of the overall strategy in the hospital. Design：Observational study. Methods：Four small bubbles were developed in the bubble management of newborns in the hospital.The COVID19 ward in Shanghai Public Health Clinical Center, as a small red bubble, was used to admit the infants with nucleic acid or antigen positive results, in accordance with the protocol set by Children's Hospital of Fudan University. The isolation ward, as a small orange bubble, was set in a separate building in the hospital including negative pressure rooms. Infants with highrisk epidemic history were admitted. All infants in the small orange bubble were required to complete a 7day medical observation and perform nucleic acid test every day. The negative pressure rooms and the nonnegative pressure rooms had their own independent places for storing materials. The staff were protected by grade II and grade I (+4) standard protective equipment respectively. The transportation of stuff and specimens was carried out by special "ferrymen". The transition ward with single rooms and multiperson rooms, as a small yellow bubble, was set to admit lowrisk epidemic history infants. Nucleic acid testing was performed every 24 hours and medical observation would be ended if nucleic acid was negative for 3 consecutive days. The single rooms and the multiperson rooms had their own independent places for storing materials. The staff were protected by grade II and grade I (+4) standard protective equipment respectively. The transportation of stuff and specimens was carried out by special "ferrymen". The clean wards, as the small green bubbles, were the areas for routine hospitalized infants as usual. They admitted defined riskfree infants from orange and yellow bubbles. The transport of infants was uniformly taken by 120 emergency vehicles of the whole city. The infants were transported to the bubble by the transport team of the corresponding bubble. Infants came out of the the small red bubble according to the protocol of COVID19 ward in the other article of the whole hospital in this issue. Infants came out of small orange bubble according to the following protocols: a.The 7days medical observation was completed; b. There was no COVID19 patients in the building of the family where the infants lived after being discharged; c. The health code of the home caregivers and the coresidents was green, or the isolation had been removed; d. The health code of the family members who took the infants out of the hospital was green, and the nucleic acid within 48 hours was negative. Infants could come out of small yellow bubble after 72h medical observation. During the hospitalization of the infants, the medical staff conveyed humanistic care to the parents of the newborn through WeChat to relieve the doubts, anxieties and difficulties of parents at any time. Main outcome measures：No occupational exposure and nosocomial infections among medical staff. Results：A total of 677 infants were admitted, of which 158 (130 from Shanghai Public Health Clinical Center, 21 from other medical institutions, and 7 transported by small orange bubble team) were admitted into the small orange bubble for management. There were 10(6.4%) premature infants out of them. The remaining 519 infants (375 from the community, 144 transported by the small yellow bubble team) admitted into the yellow bubble for management. There were 173 (33.3%) preterm infants, 82 (15.8%) infants with intubation, 45(8.7%) with noninvasive ventilation, all of whom entered the small green bubbles after medical observation, including 137 in the NICU and 382 in the general ward. The average length of stay was 13.5 days. One infant was diagnosed as complex congenital heart disease in the small orange bubble and transported to CCU after medical observation. Two infants with positive nucleic acid test in the small orange bubble who had contact history with COVID19 mothers after birth were and transported to the red bubble for management. There were 324 medical staff participating in the work of the small red, orange, yellow and green bubbles, and no occupational exposure or hospital infection occurred. Conclusion：It is feasible to implement newborn bubble management in this pandemic wave, and the effect of preventing and controlling occupational exposure and hospital infection is good.

Key words: Newborn, SARS-CoV-2, Bubble management, Occupational exposure, Nosocomial infection