Effect of 2 Inactivated SARS-CoV-2 Vaccines on Symptomatic COVID-19 Infection in Adults

Abstract

IMPORTANCE Although effective vaccines against COVID-19 have been developed, additional vaccines are still needed.OBJECTIVE To evaluate the efficacy and adverse events of 2 inactivated COVID-19 vaccines.DESIGN, SETTING, AND PARTICIPANTS Prespecified interim analysis of an ongoing randomized, double-blind, phase 3 trial in the United Arab Emirates and Bahrain among adults 18 years and older without known history of COVID-19. Study enrollment began on July 16, 2020. Data sets used for the interim analysis of efficacy and adverse events were locked on December 20, 2020, and December 31, 2020, respectively.INTERVENTIONS Participants were randomized to receive 1 of 2 inactivated vaccines developed from SARS-CoV-2 WIV04 (5 μg/dose; n = 13 459) and HB02 (4 μg/dose; n = 13 465) strains or an aluminum hydroxide (alum)-only control (n = 13 458); they received 2 intramuscular injections 21 days apart. MAIN OUTCOMES AND MEASURESThe primary outcome was efficacy against laboratory-confirmed symptomatic COVID-19 14 days following a second vaccine dose among participants who had no virologic evidence of SARS-CoV-2 infection at randomization. The secondary outcome was efficacy against severe COVID-19. Incidence of adverse events and reactions was collected among participants who received at least 1 dose. RESULTS Among 40 382 participants randomized to receive at least 1 dose of the 2 vaccines or alum-only control (mean age, 36.1 years; 32 261 [84.4%] men), 38 206 (94.6%) who received 2 doses, contributed at least 1 follow-up measure after day 14 following the second dose, and had negative reverse transcriptase-polymerase chain reaction test results at enrollment were included in the primary efficacy analysis. During a median (range) follow-up duration of 77 (1-121) days, symptomatic COVID-19 was identified in 26 participants in the WIV04 group (12.1 [95% CI,] per 1000 person-years), 21 in the HB02 group (9.8 [95% CI, 6.4-15.0] per 1000 person-years), and 95 in the alum-only group (44.7 [95% CI,] per 1000 person-years), resulting in a vaccine efficacy, compared with alum-only, of 72.8% (95% CI, 58.1%-82.4%) for WIV04 and 78.1% (95% CI, 64.8%-86.3%) for HB02 (P < .001 for both). Two severe cases of COVID-19 occurred in the alum-only group and none occurred in the vaccine groups. Adverse reactions 7 days after each injection occurred in 41.7% to 46.5% of participants in the 3 groups; serious adverse events were rare and similar in the 3 groups (WIV04: 64 [0.5%]; HB02: 59 [0.4%]; alum-only: 78 [0.6%]). CONCLUSIONS AND RELEVANCEIn this prespecified interim analysis of a randomized clinical trial, treatment of adults with either of 2 inactivated SARS-CoV-2 vaccines significantly reduced the risk of symptomatic COVID-19, and serious adverse events were rare. Data collection for final analysis is pending.

Clinical Features of Imported Chinese COVID-19 Patients Following Chinese Inactivated Vaccines Injection Abroad

“…A recent double-blind, randomized, phase 3 study performed in four Middle East countries has revealed that two inactivated SARS-CoV-2 vaccinations produced by the China National Biotec Group Company Limited signi cantly reduced the risk of symptomatic COVID-19 in adults [17]. In this study, a total of 47 symptomatic COVID-19 cases and 26 asymptomatic cases were identi ed among 25440 participants who received two doses of vaccines.…”

“…Currently, the phase 3 trial concerning the e cacy of two Chinese inactivated SARS-CoV-2 vaccines on symptomatic COVID-19 infection in adults has been released on May 26, 2021, and found that 72.8% (95% CI, 58.1%-82.4%) of vaccinees in WIV04 vaccine group and 78.1% (95% CI, 64.8%-86.3%) of vaccinees in HB02 vaccine group acquired immunity against COVID-19 during a median (range) followup duration of 77 (1-121) days [17]. Notably, 26 vaccinees were identi ed as symptomatic COVID-19 after WIV04 vaccine injections, 21 vaccinees were identi ed as symptomatic COVID-19 after HB02 vaccine injections, the corresponding incidence rate (per 1000 personyears) was 12.1 (95% CI, 8.3-17.8) in the WIV04 group, and 9.8 (95% CI, 6.4-15.0) in the HB02 group.…”

“…Notably, 26 vaccinees were identi ed as symptomatic COVID-19 after WIV04 vaccine injections, 21 vaccinees were identi ed as symptomatic COVID-19 after HB02 vaccine injections, the corresponding incidence rate (per 1000 personyears) was 12.1 (95% CI, 8.3-17.8) in the WIV04 group, and 9.8 (95% CI, 6.4-15.0) in the HB02 group. Additionally, a total of 26 asymptomatic cases of COVID-19 were diagnosed 14 days following the second dose (16 in the WIV04 group, 10 in the HB02 group) [17]. However, no study reported detailed information of clinical manifestations and prognosis of patients after Chinese inactivated vaccination.…”

“…Vaccinations have shown to be highly effective in preventing SARS-CoV-2 infections, COVID-19-related hospitalizations, severe diseases, and death [10,15]. The latest evidence indicated that no severe COVID-19 cases were identi ed after receiving the Chinese inactivated vaccines, which means an e cacy of 100% against severe COVID-19 [17]. Previous studies showed that chronic comorbidity and high BMI were the risk factors of severe COVID-19, requiring ICU care or death [20,22].…”

Reasons of Vaccine Hesitancy among Pakistanis with Available COVID-19 Vaccine: The Next Challenge in the Fight against COVID-19

“…Only expert health professionals should be engaged to address queries of the public. Most of participants had reluctance due to lack of published data on efficacy and safety of vaccine as phase III data of Sinopharm has only been published very recently, after the study had been conducted by Al Kaabi N et al [15]. The third important factor to avoid vaccination was misconception that previous COVID-19 infection is protective against reinfection and hence they do not require vaccine.…”