In this task, you're given a paragraph from the research paper and your task is to generate a suitable title for the research paper based on the given paper. Under 100 words is a good title length.

[Q]: To elucidate the impact of a hepatitis B (HB) vaccination program on the prevalence of HB surface antigen (HBsAg) and HB envelope antigen (HBeAg) as well as the success rate of HBeAg clearance among parturients, we collected data on parturients who gave birth between 2000 and 2010, and recorded the HB status postpartum of those with positive HBeAg before birth. A total of 8696 parturients were enrolled, of whom 113 with prenatal positive HBeAg were invited back. The prevalence of HBsAg decreased over the study period, particularly in the vaccinated cohort, while there was no change in the prevalence of HBeAg. Foreign parturients had a higher HBeAg-positive rate and delayed HBeAg clearance, and those with a higher body mass index (>24 kg/m 2 ) had earlier HBeAg clearance (51.9% vs. 23.9%, p = 0.005). Only 30% of the subjects who were positive for HBeAg before birth became negative 5 years after delivery. In conclusion, the downward trend in HB infection with more significance among vaccinated parturients reflects effective prevention and the impact of universal HB immunization. Nonetheless, aggressive follow-up is necessary for parturients who are persistently positive for HBeAg postpartum, as well as developing different public health policies for foreign parturients from endemic areas. Published: xx xx xxxx OPEN www.nature.com/scientificreports/ 2 Scientific RepoRts | 7: 1212 |
[A]: Changes in the Prevalence of HBsAg and HBeAg: a Study of 8696 Parturients in a Well Vaccinated Area OPEN


[Q]: Limited data exist on how SARS-CoV-2 enters and spreads in the general population. We used two strategies for SARS-CoV-2 testing: targeted testing of high-risk individuals (n=4,551) and a population screening (n=5,502). We sequenced SARS-CoV-2 from 340 individuals. RESULTS March 22 2020, 528 had tested positive for SARS-CoV-2 in the targeted testing (11.6%) and 50 in the population screening (0.9%); approximately 0.2% of the Icelandic population. Large fractions of positives had travelled outside Iceland (38.4% and 34.0%). Fewer under 10 years old were positive than those older: 2.8% vs. 12.3% for targeted testing (P=1.6e-9) and 0.0% vs. 1.0% for population screening (P=0.031). Fewer females were positive in the targeted testing than males (9.5% vs. 14.6%, P=6.8e-9). SARS-CoV-2 came from eight clades, seven A clades and one B clade. The clade composition differed between the testing groups and changed with time. In the early targeted testing, 65.0% of clades were A2a1 and A2a2 derived from Italian and Austrian skiing areas, but in the later targeted testing went down to 30.6% and were overtaken by A1a and A2a, the most common clades in the population screening. SARS-CoV-2 has spread widely in Iceland outside of the high-risk groups. Several strains cause these infections and their relative contribution changed rapidly.
[A]: Early Spread of SARS-Cov-2 in the Icelandic Population


[Q]: In this study, a high-resolution frontal area density (FAD) map that depicts the surface roughness of urban Hong Kong is produced using a mapping method that takes into account the dense urban morphology and the site wind availability of the territory. Using the MM5/CALMET model simulated wind data of Hong Kong, the FAD map of three urban zones are calculated: podium (0-15 m), building (15-60 m), and urban canopy (0-60 m). The wind tunnel test data is used to correlate the FAD understanding of the three zones. The grid sensitivity test indicates that 200 m × 200 m is the reasonable resolution for the FAD map; the test also establishes that the lower urban podium zone yields the best correlation with the experimental data. The study further establishes that the simpler two-dimensional ground coverage ratio (GCR), which is readily available in the planning circle, can be used to predict the area's average pedestrian level urban ventilation performance of the city. Working with their inhouse GIS team using available data, it allows the planners a way to understand the urban ventilation of the city for decisions related to air paths, urban permeability and site porosity.
[A]:
Improving the wind environment in high-density cities by understanding urban morphology and surface roughness: A study in Hong Kong