Kwesi-Maliepaard Eliza Mari, Alhassan Yakubu, Quaye Emmanuel K, Kotey Vera M, Mohammed Aisha M, Agyemang Seth, Sromani Adelaide K, Darko Stephanie, Buadii Erica, Tackie Randy, Akligoh Harry, Ibrahim Barikisu, Hutchful David, Paemka Lily, Amoako Emmanuella, Ngoi Joyce M, Manu Aida, Greenwood David, Carr Edward J, Wu Mary Y, Bauer David L V, Wall Emma C, Dey Dzifa, Quao Abdul Razak, Ayisi Akosua, Amponsa-Achiano Kwame, Bekoe Franklin Asiedu, Awandare Gordon, Quashie Peter K, Bediako Yaw
Yemaachi Biotech, Accra, Ghana.
Department of Biostatistics, School of Public Health, University of Ghana, Accra, Ghana.
BMC Med. 2025 May 28;23(1):312. doi: 10.1186/s12916-025-04157-0.
Little data exist on the COVID-19 vaccine response in African countries who despite having high disease burden, have low COVID-19 mortality rates. We investigated the longitudinal immune response in a West-African urban population upon COVID-19 vaccination, two years after the start of the pandemic.
The HERITAGE study is a prospective cohort study of 301 residents of Accra, Ghana. Participants received two doses of a COVID-19 vaccine (AZD1222 or BNT162b2) from December 2021 and were followed-up for 12 months. COVID-19 status was determined by RT-PCR at seven time points. Serological responses, including anti-Nucleocapsid IgG, anti-Spike IgG and live-virus neutralisation were determined at four time points during the 12 months follow-up.
COVID-19 positivity was 19.3% at baseline and reduced rapidly upon vaccination. Serological analyses indicated previous exposure to SARS-CoV-2 in 80.5% of the HERITAGE participants. After vaccination, neutralising antibody titres (NAbTs) against six different SARS-CoV-2 variants significantly (p < 0.001) increased, with fold changes (FC) ranging from 1.87 to 4.59. Highest NAbTs were recorded in the previously exposed group. Participants without prior exposure showed a continues increase in NAbTs between months 3 and 12 for circulating variants (Omicron B.A2 (FC 2.44, p < 0.001) and XBB.1.5 (FC 1.91, p = 0.05)). By comparison a matched cohort from the UK-based LEGACY study showed generally lower NAbTs at baseline (HERITAGE vs LEGACY for Wild-type: 250.3 vs 141.3, p < 0.0001, for A.27 84.6 vs 43.2, p = 0.0129, for Eta 159.7 vs 118.1, p = 0.3428, for Delta 158.6 vs 10.0, p < 0.0001, for Omicron B.A2 153.7 vs 10.0, p < 0.0001) and after receiving the vaccine (HERITAGE vs LEGACY for Wild-type: 882.6 vs 337.7, p < 0.0001, for A.27 552.0 vs 227.7, p = 0.0001, for Eta 682.2 vs 295.3, p < 0.0001, for Delta 557.6 vs 165.1, p < 0.0001, for Omicron B.A2 283.3 vs 124.2, p < 0.0001). NAbTs kinetics between the two cohorts were more similar when analysis was restricted to previously unexposed participants when adjusted for circulating variants during the sampling period.
Two doses of AZD1222 or BNT162b2 significantly increased existing NAbTs against SARS-CoV-2 in a highly exposed population, showing durable boosting of pre-existing infection-induced immunity. This indicates the importance of considering local population exposure in vaccination design and deployment.
尽管非洲国家疾病负担沉重，但新冠病毒疾病（COVID-19）死亡率较低，关于这些国家COVID-19疫苗接种反应的数据很少。我们调查了疫情开始两年后，西非城市人口接种COVID-19疫苗后的纵向免疫反应。
HERITAGE研究是一项对加纳阿克拉301名居民进行的前瞻性队列研究。参与者从2021年12月开始接种两剂COVID-19疫苗（AZD1222或BNT162b2），并随访12个月。在七个时间点通过逆转录聚合酶链反应（RT-PCR）确定COVID-19感染状况。在12个月的随访期间，于四个时间点测定血清学反应，包括抗核衣壳IgG、抗刺突IgG和活病毒中和反应。
基线时COVID-19阳性率为19.3%，接种疫苗后迅速下降。血清学分析表明，HERITAGE研究中80.5%的参与者既往接触过严重急性呼吸综合征冠状病毒2（SARS-CoV-2）。接种疫苗后，针对六种不同SARS-CoV-2变体的中和抗体滴度（NAbTs）显著（p < 0.001）升高，倍数变化（FC）范围为1.87至4.59。既往接触过病毒的组中NAbTs最高。既往未接触过病毒的参与者在第3至12个月期间，针对流行变体（奥密克戎BA.2（FC 2.44，p < 0.001）和XBB.1.5（FC 1.91，p = 0.05））的NAbTs持续升高。相比之下，来自英国LEGACY研究的匹配队列在基线时（野生型：HERITAGE研究与LEGACY研究相比为250.3 vs 141.3，p < 0.0001；A.27为84.6 vs 43.2，p = 0.0129；伊塔为159.7 vs 118.1，p = 0.3428；德尔塔为158.6 vs 10.0，p < 0.0001；奥密克戎BA.2为153.7 vs 10.0，p < 0.0001）以及接种疫苗后（野生型：HERITAGE研究与LEGACY研究相比为882.6 vs 337.7，p < 0.0001；A.27为552.0 vs 227.7，p = 0.0001；伊塔为682.2 vs 295.3，p < 0.0001；德尔塔为557.6 vs 165.1，p < 0.0001；奥密克戎BA.2为283.3 vs 124.2，p < 0.0001）的NAbTs普遍较低。当在采样期间针对流行变体进行调整后，仅分析既往未接触过病毒的参与者时，两个队列之间的NAbTs动力学更为相似。
两剂AZD1222或BNT162b2显著提高了高暴露人群中针对SARS-CoV-2的现有NAbTs，显示出对既往感染诱导的免疫力的持久增强。这表明在疫苗接种设计和部署中考虑当地人群暴露情况的重要性。
