Prevalence of serum neutralizing antibodies to adenovirus type 5 (Ad5) and 41 (Ad41) in children is associated with age and sanitary conditions.

Neutralizing antibody (NAb) can dampen the immunogenicity of adenovirus (Ad) vector-based vaccine. Vector systems based on human adenovirus type 41 (Ad41) have been constructed and used to develop recombinant vaccines. Here, we attempted to study the seroprevalence of NAbs to Ad5 and Ad41 among children and adults in Qinghai province, China. The positive rates (titer⩾40) of Ad5 and Ad41 NAb in adults from Xining city were 75.7% and 94.7%, respectively. The moderate/high-positive rates (titer⩾160) of NAb were quite close between the two viruses in adults (70.4% for Ad5 and 73.5% for Ad41). Age-dependent increase of NAb seroprevalence was observed for both viruses in children. NAb-positive rate of Ad41 reached 50% at 3.3-4.6years of age for children from Chengxi district, Xining city, approximately 1.5years earlier than that of Ad5 did. Interestingly, NAb level was also associated with sanitary conditions among young children. For Ad5, 8-15% children (0.2-3.0years of age) from city or town, where the sanitations were relatively better, had moderate/high-positive NAb, while the same rate was 62% for children from villages. For Ad41, 22% children from city, 47% from town and 88% from villages possessed moderate/high-positive NAb. The possible influence of NAb titer distributions on the application of Ad41-vectored vaccines was discussed in detail. Our results suggested that children from places with poor sanitations should be included for comprehensive Ad NAb seroprevalence studies, and provided insights to the applications of Ad41 vectors.

[Study on the probability of hepatitis B virus infection at public service places].

OBJECTIVE: To provide data for the control and prevention of hepatitis B and HBV surface antigen (HBsAg) status among the appliances and practitioners working in the public service places. METHODS: 63 beauty parlors, barber shops and bathing centers selected under stratified randomization sampling method and 682 workers were investigated through questionnaire. HBsAg from th e appliances of the public service places and employee was detected by RIA. RESULTS: Two main sanitizing modes that including alcohol cleaning (34.60%) and ultraviolet light disinfection (30.79%) were used. The rates of testing on HBsAg among the appliances were 2.13% at the public service places, and were 0.63%, 2.67% and 3.70% in large-, medium- and small-sized appliances respectively. The rate of testing on HBsAg on large-, medium- and small- sized appliances were statistically different (chi2 = 6.68, P < 0.05). The positive rates of HBsAg on the appliances of beauty parlors, barbering shops and footbath inns were 2.97%, 0.61% and 3.42% respectively. People working in different service sites had different rates of HBsAg: those who worked at the 'acne needle' and the forceps were 5.13% and 4.17%. The positive rate of HBsAg among the workers in the public service places was 7.13%. The rates of HBsAgamong the workers in large-, medium- and small-sized public service places were 7.34%, 8.33% and 2.94% respectively. The rates of HBsAg among the workers in beauty parlors, barbering shops, footbath inns and bathing centers were 9.01%, 6.37%, 4.35% and 7.29% respectively. HBsAg positive rates were different among the workers working at different service sites: 13.33% at tattoo business, 12.68% in pedicles workers and 8.03% in massagists. CONCLUSION: It is important to improve the sanitizing management of the appliances used in the public service places and to improve the knowledge, attitude, as well as practice of vaccination on hepatitis B among those populations.