Bary Farha, Karunananda Maneshka Vindesh, Jeewandara Chandima, Danasekara Saubhagya, Guruge Dinuka, Rizan Rizna, Aberathna Inoka Sepali, Ranasinghe Thushali, Kuruppu Heshan, Jayamali Jeewantha, Perera Lahiru, Chathurangika Harshani, Gunaratne Amaya, Dasanthi Naduni, Ranatunga Chathura, Shashini Ishara A W, Yatiwelle Sathsara, Wijayamuni Ruwan, Tan Tiong Kit, Townsend Alain, Ogg Graham S, Malavige Gathsaurie Neelika
Allergy Immunology and Cell Biology Unit, Department of Immunology and Molecular Medicine, University of Sri Jayewardenepura, Nugegoda, Sri Lanka.
Colombo Municipal Council, Colombo, Sri Lanka.
J Med Virol. 2025 Jul;97(7):e70462. doi: 10.1002/jmv.70462.
To understand how the population immunity evolved over time and possible susceptibility of the Sri Lankan population to emerging SARS-CoV-2 variants, we proceeded to evaluate the changes in antibody positivity rates to omicron variants BA.2.75 and XBB.1.5 and for selected sarbecoviruses. The haemagglutination test was carried out to determine the presence of antibodies against the RBD of the SARS-CoV-2 omicron variants XBB.1.5 and BA.2.75 and the RBD of the sarbecoviruses RaTG13, WIV1, Khosta-2, and SARS-CoV-1, in individuals aged 5-80 years of age in years 2020 (n = 381), 2022 (n = 432), and 2023 (n = 382). The highest positivity rates for BA.2.75, RaTG13, WIV1, Khosta-2, and SARS-CoV-1 were seen in 2022, with positivity rates significantly declining for many of the viruses except XBB.1.5 and Khosta-2 by 2023. The positivity rates for Khosta-2 (p < 0.001) and WIVI (p < 0.001) were significantly lower in children < 14 years age, but not for XBB.1.5, BA.2.75, and RaTG13. Children < 14 years who were SARS-CoV-2 unvaccinated had the lowest positivity rates for all tested viruses except BA.2.75. Less than 20% of individuals in all age groups had antibody titers equivalent to 1:80, which corresponds to neutralizing antibody titers by 2023. Population immunity to omicron SARS-CoV-2 variants and selected sarbecoviruses had significantly declined in Colombo, Sri Lanka by 2023. Therefore, although T cells might still offer some protection against severe disease, immunizing vulnerable individuals in the community with protective vaccine designs might be important to consider at this stage.
为了解群体免疫力如何随时间演变以及斯里兰卡人群对新出现的SARS-CoV-2变体的可能易感性，我们着手评估针对奥密克戎变体BA.2.75和XBB.1.5以及选定的沙贝病毒的抗体阳性率变化。对2020年（n = 381）、2022年（n = 432）和2023年（n = 382）年龄在5至80岁的个体进行了血凝试验，以确定针对SARS-CoV-2奥密克戎变体XBB.1.5和BA.2.75以及沙贝病毒RaTG13、WIV1、Khosta-2和SARS-CoV-1的受体结合域（RBD）的抗体的存在情况。BA.2.75、RaTG13、WIV1、Khosta-2和SARS-CoV-1的最高阳性率出现在2022年，到2023年，除XBB.1.5和Khosta-2外，许多病毒的阳性率显著下降。14岁以下儿童中Khosta-2（p < 0.001）和WIVI（p < 0.001）的阳性率显著较低，但XBB.1.5、BA.2.75和RaTG13并非如此。14岁以下未接种SARS-CoV-2疫苗的儿童，除BA.2.75外，所有检测病毒的阳性率最低。到2023年，所有年龄组中不到20%的个体的抗体滴度相当于1:80，这相当于中和抗体滴度。到2023年，斯里兰卡科伦坡对奥密克戎SARS-CoV-2变体和选定沙贝病毒的群体免疫力显著下降。因此，尽管T细胞可能仍能为严重疾病提供一些保护，但在现阶段考虑用保护性疫苗设计为社区中的脆弱个体接种疫苗可能很重要。
