Intapiboon Porntip, Seepathomnarong Purilap, Ongarj Jomkwan, Surasombatpattana Smonrapat, Uppanisakorn Supattra, Mahasirimongkol Surakameth, Sawaengdee Waritta, Phumiamorn Supaporn, Sapsutthipas Sompong, Sangsupawanich Pasuree, Chusri Sarunyou, Pinpathomrat Nawamin
Department of Internal Medicine, Faculty of Medicine, Prince of Songkla University, Songkhla 90110, Thailand.
Department of Biomedical Sciences and Biomedical Engineering, Faculty of Medicine, Prince of Songkla University, Songkhla 90110, Thailand.
Vaccines (Basel). 2021 Nov 23;9(12):1375. doi: 10.3390/vaccines9121375.
Effective vaccine coverage is urgently needed to tackle the COVID-19 pandemic. Inactivated vaccines have been introduced in many countries for emergency usage, but have only provided limited protection. Heterologous vaccination is a promising strategy to maximise vaccine immunogenicity. Here, we conducted a phase I, randomised control trial to observe the safety and immunogenicity after an intradermal boost, using a fractional dosage (1:5) of BNT162b2 mRNA vaccine in healthy participants in Songkhla, Thailand. In total, 91 volunteers who had been administered with two doses of inactivated SARS-CoV-2 (CoronaVac) were recruited into the study, and then randomised (1:1:1) to received different regimens of the third dose. An intramuscular booster with a full dose of BNT162b2 was included as a conventional control, and a half dose group was included as reciprocal comparator. Both, immediate and delayed adverse events following immunisation (AEFI) were monitored. Humoral and cellular immune responses were examined to observe the booster effects. The intradermal booster provided significantly fewer systemic side effects, from 70% down to 19.4% ( < 0.001); however, they were comparable to local reactions with the conventional intramuscular booster. In the intradermal group after receiving only one fifth of the conventional dosage, serum Anti-RBD IgG was halved compared to the full dose of an intramuscular injection. However, the neutralising function against the Delta strain remained intact. T cell responses were also less effective in the intradermal group compared to the intramuscular booster. Together, the intradermal booster, using a fractional dose of BNT162b2, can reduce systemic reactions and provides a good level and function of antibody responses compared to the conventional booster. This favourable intradermal boosting strategy provides a suitable alternative for vaccines and effective vaccine management to increase the coverage during the vaccine shortage.
迫切需要有效的疫苗接种覆盖率来应对新冠疫情。许多国家已引入灭活疫苗用于紧急使用，但仅提供了有限的保护。异源接种是使疫苗免疫原性最大化的一种有前景的策略。在此，我们在泰国宋卡的健康参与者中进行了一项I期随机对照试验，以观察使用BNT162b2 mRNA疫苗的五分之一剂量进行皮内加强接种后的安全性和免疫原性。总共招募了91名已接种两剂灭活新冠病毒疫苗（科兴疫苗）的志愿者进入研究，然后将他们随机分为三组（1:1:1）接受不同的第三剂接种方案。将一剂完整剂量的BNT162b2肌肉注射加强针作为传统对照，将半剂量组作为相互对照。监测了免疫接种后的即时和延迟不良事件（AEFI）。检测了体液和细胞免疫反应以观察加强针的效果。皮内加强针产生的全身副作用显著减少，从70%降至19.4%（<0.001）；然而，它们与传统肌肉注射加强针的局部反应相当。在皮内接种组中，仅接受传统剂量的五分之一后，血清抗RBD IgG与全剂量肌肉注射相比减半。然而，对德尔塔毒株的中和功能保持完整。与肌肉注射加强针相比，皮内接种组的T细胞反应也较弱。总体而言，使用BNT162b2的部分剂量进行皮内加强接种可以减少全身反应，并且与传统加强针相比提供了良好水平的抗体反应和功能。这种有利的皮内加强接种策略为疫苗和有效的疫苗管理提供了合适的替代方案，以在疫苗短缺期间提高接种覆盖率。
