Research press release



Vaccines: SARS-CoV-2 RNA vaccine candidate induces immune response in phase 1/2 trial

RNAワクチン候補「BNT162b1」の第1/2相臨床試験の中間報告がNature に掲載される。BNT162b1が18~55歳の健康な成人に強力な免疫応答を誘導したことが明らかになった。


この論文で、Judith Absalonらは、現在実施されているBNT162b1の第1/2相臨床試験の中間データを報告している。この試験には、18~55歳の健康な成人45人(男性23人、非妊娠女性22人、白人は37人)が参加し、10 μg、30 μg、100 μgのBNT162b1投与群とプラセボ投与群に無作為に割り付けられた。10 μgと30 μgのBNT162b1投与群の参加者は、21日目に2回目のワクチン接種を受けた。この臨床試験では、BNT162b1の忍容性はおおむね良好であるが、ワクチン接種後7日間に一部の参加者に軽度から中等度の副作用(注射部位の疼痛、疲労感、頭痛、発熱、睡眠障害など)が認められ、ワクチンの接種量が多いと副作用が重いことが分かった。

BNT162b1は、参加者に強力な免疫応答を誘導し、接種量が多くなると免疫応答の強さが増し、2回のワクチン接種を受けた場合の方が免疫応答は強かった。単回接種の場合には、いずれの接種量でも接種の21日後にSARS-CoV-2に対する抗体が検出され、2回接種の場合には、2回目のワクチン接種(10 μgまたは30 μg)の7日後にSARS-CoV-2中和抗体がかなり増加した。免疫応答は、10 μg投与群よりも30 μg投与群の方がはるかに強かった。しかし、30 μg投与群と100 μg投与群との間には、1回目のワクチン接種後に誘導された免疫応答に顕著な差は認められなかった。100 μg投与群の参加者は、副作用がより重かったため、2回目のワクチン接種は行われなかった。


An RNA vaccine candidate, BNT162b1, is shown to induce a robust immune response in healthy adults aged 18–55 years in an interim report of a phase 1/2 clinical trial published in Nature.

RNA vaccine platforms, which use messenger RNA to elicit an immune response, are generally considered safe and have facilitated the rapid development of vaccines against SARS-CoV-2. Delivered intramuscularly, BNT162b1, which encodes a SARS-CoV-2 receptor-binding domain antigen, is one of several RNA vaccine candidates that are being studied in parallel for selection to advance to a trial of their safety and efficacy.

Judith Absalon and colleagues report interim data from an ongoing phase 1/2 clinical study of BNT162b1. Forty-five healthy adults (23 men and 22 non-pregnant women; 37 participants were white) aged 18–55 years were randomized to receive 10 micrograms (μg), 30 μg or 100 μg of BNT162b1, or a placebo. Participants in the 10-μg and 30- μg groups also received a second dose on day 21. The authors found that BNT162b1 was generally well-tolerated, although some participants experienced mild to moderate side effects, which increased with dose level, in the seven days following vaccination, including pain at the injection site, fatigue, headache, fever and sleep disturbance.

The vaccine elicited a robust immune response in participants, which increased with dose level and with a second dose. Antibodies against SARS-CoV-2 were present 21 days after a single vaccination at all dose levels, and there was a substantial increase in SARS-CoV-2-neutralizing antibodies 7 days after the second 10-μg or 30-μg dose was given. The immune response was much stronger in the 30-μg group than in the 10-μg group. However, there were no notable differences in immune response between the 30-μg and 100-μg groups after one dose, and as participants who received the 100-μg dose also experienced greater side effects, they did not receive a second dose.

Participants’ levels of neutralizing antibodies were 1.9 to 4.6 times higher than those in patients recovering from SARS-CoV-2 infection. However, although this comparison provides a benchmark for evaluating the vaccine-elicited immune response and the vaccine’s potential to provide protection, phase 3 trials are needed to determine the efficacy of BNT162b1. The study is also enrolling adults aged 65–85 years, and later phases will prioritize the enrolment of more-diverse populations.

doi: 10.1038/s41586-020-2639-4

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