Neutralizing Antibody Responses against Five SARS-CoV-2 Variants and T Lymphocyte Change after Vaccine Breakthrough Infections from the SARS-CoV-2 Omicron BA.1 Variant in Tianjin, China: A Prospective Study / 生物医学与环境科学（英文）

OBJECTIVE@#To investigate whether Omicron BA.1 breakthrough infection after receiving the SARS-CoV-2 vaccine could create a strong immunity barrier.@*METHODS@#Blood samples were collected at two different time points from 124 Omicron BA.1 breakthrough infected patients and 124 controls matched for age, gender, and vaccination profile. Live virus-neutralizing antibodies against five SARS-CoV-2 variants, including WT, Gamma, Beta, Delta, and Omicron BA.1, and T-lymphocyte lymphocyte counts in both groups were measured and statistically analyzed.@*RESULTS@#The neutralizing antibody titers against five different variants of SARS-CoV-2 were significantly increased in the vaccinated population infected with the Omicron BA.1 variant at 3 months after infection, but mainly increased the antibody level against the WT strain, and the antibody against the Omicron strain was the lowest. The neutralizing antibody level decreased rapidly 6 months after infection. The T-lymphocyte cell counts of patients with mild and moderate disease recovered at 3 months and completely returned to the normal state at 6 months.@*CONCLUSION@#Omicron BA.1 breakthrough infection mainly evoked humoral immune memory in the original strain after vaccination and hardly produced neutralizing antibodies specific to Omicron BA.1. Neutralizing antibodies against the different strains declined rapidly and showed features similar to those of influenza. Thus, T-lymphocytes may play an important role in recovery.

Evaluation of effect of community-based HIV/AIDS interventions among men who have sex with men in eighteen cities, China / 中华预防医学杂志

<p><b>OBJECTIVE</b>To evaluate the effect of a community-based intervention project among men who have sex with men (MSM) after two-year implementation.</p><p><b>METHODS</b>Comprehensive interventions among MSM in 18 cities of seven provinces were conducted. The pre-intervention questionnaire was conducted in September 2006 and 5178 subjects were investigated through snowball method. In May 2007, post-questionnaire was conducted and 5460 subjects were investigated through snowball or accompanied recommendation method. For each subject, a questionnaire was completed, including basic information, HIV/AIDS knowledge, behaviours and intervention status. At the same time, 5 ml intravenous blood sample was collected to detect HIV infection and evaluated the intervention effect.</p><p><b>RESULTS</b>After two-year implementation, the awareness rate of HIV/AIDS knowledge increased from 76.0% (3933/5178) in 2006 to 90.5% (4943/5460) in 2008 (chi(2) = 451.786, P < 0.001); the rate of condom use in the last anal sex with males increased from 58.0% (2382/4105) to 76.7% (3643/4750) (chi(2) = 215.491, P < 0.01); the rate of consistent condom use in the last six months increased from 28.2% (1163/4118) to 44.5% (2114/4753) (chi(2) = 264.606, P < 0.01); the proportion of MSM receiving HIV antibody test increased from 18.8% (973/5170) to 39.1% (2136/5454) (chi(2) = 530.181, P < 0.01); and the HIV infection rate increased from 2.3% (118/5178) to 5.0% (271/5427) (chi(2) = 47.613, P < 0.01).</p><p><b>CONCLUSION</b>The MSM community-based intervention project achieved some good results after two-year implementation and contributed to an increase in HIV/AIDS knowledge and safe sex.</p>