CORONAVIRUS

Coronavirus vaccine update: China gets promising early results from Covid-19 trial

There was encouraging news this weekend - a coronavirus vaccine tested for the first time in humans is safe and induces a rapid immune response.

Coronavirus vaccine update: China gets promising early results from Covid-19 trial
Dado Ruvic REUTERS

The coronavirus vaccine currently being developed in China by CanSino Biologics Inc. has given hope that a safe drug to combat Covid-19 could be a reality sometime soon although researchers are still in the dark about the effectiveness of a single one-dose treatment.

China trials for Covid-19 vaccine

In a report published in medical journal, The Lancet, Professor Wei Chen from the Beijing Institute of Biotechnology detailed how the vectored vaccine Ad5-nCoV has been tested in a group of 108 healthy adults aged from between 18 to 60 years in Wuhan, China, where the pandemic began.

The 108 participants (51% male, 49% female with a mean age of 36.3 years) were split into three groups, each one given the low dose (n=36), middle dose (n=36), or high dose (n=36) of the vaccine. Their health was closely monitored for 28 days after the vaccine was administered by intramuscular injection.

Mild reactions to Covid-19 vaccine

At least one mild, adverse reaction within the first 7 days after the vaccination was reported in 30 (83%) participants in the low dose group, 30 (83%) participants in the middle dose group, and 27 (75%) participants in the high dose group. But none of the participants reported serious reactions to the vaccine – the most common reaction was tenderness around the zone of injection (54%), fever, fatigue, headache and muscular aches.

Within two weeks of getting the vaccine, the immune systems of people receiving all three doses showed some level of response, with most developing ELISA antibodies which can attach to the virus, but not neutralise it. Antibodies peaked at 28 days post-vaccination. Specific T-cell response peaked at day 14 post-vaccination. The first-in-human trial showed that the Ad5 vectored Covid-19 vaccine was tolerable and immunogenic in healthy adults.

"These results represent an important milestone. The trial demonstrates that a single dose of the new adenovirus type 5 vectored COVID-19 (Ad5-nCoV) vaccine produces virus-specific antibodies and T cells in 14 days, making it a potential candidate for further investigation," Professor Wei Chen said. "However, the ability to trigger these immune responses does not necessarily indicate that the vaccine will protect humans from Covid-19... we are still a long way from this vaccine being available to all."

Covid-19 vaccine projects around the world

More than 100 vaccine candidates against SARS-CoV-2 are in development worldwide, with about 12 in human testing designed to mainly evaluate safety. The ChAdOx1 nCoV-19 vaccine being developed at the University of Oxford is ready for a large-scale human clinical trial involving 10,000 volunteers. In Russia, the Gamalei Institute of Epidemiology and Microbiology has successfully tested their Covid-19 vaccine on monkeys and are set for trials on humans by mid-June.