US-based Moderna, one of the frontrunners in developing a COVID-19 vaccine, released a 135-page document on Thursday, 17 September, with details of the latest trials of its vaccine candidate.

According to a New York Times report, the document states how safety and efficacy for the potential vaccine are being measured in this late-stage trial.

The pharmaceutical company shared that the preliminary evaluation of trial data will be conducted by late December. It also suggests that the data may not contain sufficient evidence to establish whether the vaccine works. Successive trials, to be held in March and May next year, are more likely to provide a conclusive answer.

The technology in use by Moderna is relatively new - it involves using genetic material from the virus called mRNA. This method has not been used to create a vaccine so far.

It uses a genetic platform called mRNA, short for messenger RNA, which directs the body’s cells to stimulate the immune system. The vaccine, developed using previous studies of related coronaviruses such as SARS and MERS, has already shown promise in animal models.

The company is currently conducting a Phase-3 study with the enrollment of over 23,000 out of its targeted 30,000 volunteers. Dr Tal Zaks, Moderna’s Chief Medical Officer, expects the enrollment process to be complete in the next few weeks.

Diversity of the sample has been given importance in the enrollment process. Of the total number of participants, approximately 27 percent are Black, Latino or from other racial or ethnic groups that have been particularly impacted by the disease.

The volunteers will then be monitored closely to check if they test positive for the virus or develop symptoms of COVID-19.

Side effects of the vaccine will be monitored as well. The vaccine may lead to temporary reactions in the volunteers, such as a sore arm, chills, fatigue, fever, muscle and joint pain, and headaches. The participants will be required to record their symptoms in electronic diaries, by taking their own temperatures, making clinic visits and receiving periodic phone calls to gauge their condition.

In order to assess the vaccine’s efficacy, the number of COVID-19 cases will be counted among the participants who had received both shots of the vaccine.

A total of 151 cases, spread over both the vaccine and placebo groups, would be required to establish that the vaccine is 60 per cent effective. The Food and Drug Administration (FDA) has set the bar at 50 per cent.

Some of the participants have already received the vaccine two shots, but Dr Zaks stated that he did not know if any of them had contracted the COVID-19 infection.

(With inputs from The New York Times)