In the Phase $1$ and Phase $2$ trials of the BBIBP-CorV inactivated SARS-CoV-2 vaccine, the following safety and immunogenicity results were observed:

• Phase $1$: $192$ individuals were enrolled. Of the $144$ who received the vaccine, $42$ reported an adverse reaction within the first seven days, with fever being the most common. No severe adverse reactions were reported within $28$ days after vaccination; all were classified as mild or moderate. On day $42$, neutralizing antibody geometric mean titres were higher in vaccinated individuals than in the placebo group.
• Phase $2$: $448$ individuals were enrolled. Of the $336$ who received the vaccine, $76$ reported an adverse reaction within the first seven days, again most commonly fever. All adverse reactions were mild or moderate. On day $28$, neutralizing antibody titres were significantly higher in individuals receiving a two-dose schedule ($4$ µg on days $0$ and $14$, days $0$ and $21$, and days $0$ and $28$) compared to a single-dose schedule ($8$ µg on day $0$).