Chinese Researchers Report on First Human Trial of COVID-19 Vaccine

COVID-19 Vaccine Urgently Required for Long-Term Pandemic Solution

Since the initial reports of SARS-CoV-2 infections in late 2019, the COVID-19 pandemic has rapidly spread across the globe. By early May 2020, the World Health Organization (WHO) reported over 4.7 million confirmed cases in 215 countries, resulting in more than 316,000 fatalities. The ongoing treatment efforts and measures to curb the virus’s spread have significantly strained healthcare systems and economies worldwide. Consequently, an effective COVID-19 vaccine is critically needed as a sustainable solution to manage the pandemic. Currently, there are over 100 candidate vaccines in development, with approximately eight having progressed to human clinical trials. Recently, a research team from China shared preliminary findings from the first human trial of a potential COVID-19 vaccine in the journal The Lancet.

First Human Trial of COVID-19 Vaccine Shows Immune Response

Researchers at the Beijing Institute of Biotechnology have developed a COVID-19 vaccine known as Ad5-nCoV, which utilizes a modified common cold virus (adenovirus) to carry genetic material from the SARS-CoV-2 virus. This vaccine is designed to infect human cells without causing disease, thereby stimulating the immune system to combat the SARS-CoV-2 virus.

The initial clinical trial, conducted in Wuhan, China, evaluated the safety and immune response generated by the Ad5-nCoV vaccine at varying doses. A total of 108 healthy adults, aged 18 to 60, were randomly assigned to receive low, medium, or high doses of the vaccine. Researchers monitored participants’ blood for specific antibodies and T cells—immune cells essential for fighting infections—at regular intervals following vaccination. They also tracked any potential side effects.

Results indicated that the vaccine was well-tolerated across all doses, with no serious side effects reported within 28 days post-vaccination. The most common mild side effects included injection site pain, fever, fatigue, and headache, all of which resolved quickly.

Within two weeks of vaccination, the participants exhibited immune responses characterized by binding antibodies that can attach to the SARS-CoV-2 virus. By 28 days, most participants experienced a four-fold increase in these binding antibodies. Notably, half of the participants in the low and medium-dose groups and three-quarters in the high-dose group developed neutralizing antibodies against the virus. Additionally, a rapid T cell response was observed in the majority of volunteers, particularly in the medium and high-dose groups, peaking at 14 days after vaccination.

Larger Trial of the Ad5-nCoV Vaccine Underway

Encouraged by these initial findings, researchers have launched a larger, placebo-controlled clinical trial involving 500 volunteers in Wuhan. This new study aims to replicate the initial results and assess any adverse events occurring up to six months post-vaccination. It will also include participants over the age of 60, a critical demographic for vaccine efficacy.

However, lead researcher Professor Wei Chen from the Beijing Institute of Biotechnology emphasizes caution: “The challenges in the development of a COVID-19 vaccine are unprecedented, and the ability to trigger these immune responses does not necessarily indicate that the vaccine will protect humans from COVID-19. This result shows a promising vision for the development of COVID-19 vaccines, but we are still a long way from this vaccine being available to all.”

References

1. Zhu FC, Li YH, Guan XH, et al. Safety, tolerability, and immunogenicity of a recombinant adenovirus type-5 vectored COVID-19 vaccine: a dose-escalation, open-label, non-randomized, first-in-human trial. The Lancet, Published online: May 22, 2020. https://doi.org/10.1016/S0140-6736(20)31208-3.
2. The Lancet, News release, May 22, 2020. “The Lancet: First human trial of COVID-19 vaccine finds it is safe and induces rapid immune response.” https://www.eurekalert.org/pub_releases/2020-05/tl-tlf052220.php