Where are we with COVID-19 vaccine development?

A staff member places a coronavirus vaccine candidate from Sinovac Biotech at its booth for display during the 2020 China International Fair for Trade in Services, following the COVID-19 outbreak, in Beijing, China Sept.5. Reuters-Yonhap

By Bahk Eun-ji

The global competition to develop a COVID-19 vaccine has been intensifying as it is considered to be the only fundamental solution to ending the pandemic. As some research institutes and multinational pharmaceutical and bio companies have recently entered Phase 3 clinical trials, expectations for the possibility of an early supply are also growing.

According to the Coronavirus Vaccine Tracker of the New York Times, Modena, Pfizer in the United States; AstraZeneca and Oxford University in the United Kingdom; BioNTech in Germany; CanSino Biologics, Sinovac Biotech, Wuhan Institute of Biological Products, and Sinopharm Group in China; Gamaleya Research Institute in Russia; and Murdoch Children's Research Center in Australia are in the third phase of clinical trials.

Among them, AstraZeneca said Sept. 9 that it had paused global trials, including a large late-stage one, of its experimental coronavirus vaccine because of an unexplained illness in a study participant. The company's vaccine development has been widely seen as one of the leading global candidates against the virus.

AstraZeneca and Oxford University have been conducting their Phase 3 clinical trial for vaccine candidate AZD1222 in numerous countries including the U.S, U.K., Brazil and South Africa.

Oxford University said in its initial clinical trial published in July that 1,077 adults were given the vaccine candidate, which resulted in an increase in protective neutralizing antibodies and immune T cells in the bodies of all participants. Antibodies and T cells are known to play a role in destroying viruses.

However, the suspension of the trial dims prospects for a potential year-end rollout its lead developer had signaled earlier.

Pharmaceutical and bio companies in the U.S. are also speeding up their competition to develop vaccines. In July, Moderna published the results of clinical first-phase trials of the vaccine candidate mRNA-1273 in the New England Journal of Medicine. Moderna explained that antibodies were formed by all 45 participants in the Phase 1 clinical trial. Pfizer also announced that it succeeded in inducing immune responses, including the formation of neutralizing antibodies, in its second clinical trial of 60 subjects with Germany's BioNTech.

China and Russia are also pursuing the U.S. and the U.K. companies by developing their own vaccines.

Chinese companies have also joined the third phase of clinical trials, taking advantage of their strength in early vaccine research. CanSino Biologics announced that the vaccine candidate Ad5-nCoV jointly developed by a research institute at the Academy of Military Science (AMS) caused a high level of immune response in their clinical trials.

CanSino Biologics was approved by the country's Central Military Commission last month and has been used for military purposes. In addition, Sinovac Biotech's COVID-19 vaccine candidate was authorized for emergency use in China under a program to immunize high-risk populations. China National Biotec, a unit of state-owned Sinopharm Group also received emergency use authorization for a coronavirus vaccine last month.

Russia is also confident of the success of its vaccine development. Russia will begin clinical Phase 3 testing of the vaccine Sputnik V, which is under development at the Gamaleya Institute of Epidemiology And Microbiology as early as September.

Russia is promoting the safety and effectiveness of the vaccine to the extent that President Vladimir Putin's daughter participated in clinical trials. Sputnik V has already been approved for emergency use and is being administered to high-risk groups.

Korea, however, is still running at a slower pace than other countries when it comes to developing a vaccine for COVID-19.

Genexine, the only domestic company, started Phase 1 and 2 clinical trials in June. The government is supporting companies with the goal of development sometime next year. Along with Genexine, SK Bioscience and GeneOne Life Science have been included in the government's list for clinical trial support.

Different views on vaccine development

Then how long will it take to develop a COVID-19 vaccine?

In general, vaccine development can take anywhere from two to 10 years. This is because the Phase 3 test requires tens of thousands of research cases to verify safety and effectiveness. For this reason, countries are taking steps to reduce the development period by supporting pharmaceutical companies and easing regulations.

The U.S. Food and Drug Administration (FDA) said any COVID-19 vaccine that prevents disease or decreases its severity in at least 50 percent of the people who receive it can win regulatory approval. In order to develop vaccines quickly, the FDA lowered the standard from the previous 70 percent efficacy.

There are also companies that are targeting development within this year. Assuming that the time taken for Phase 3 clinical trials becomes shorter ― three to 6 months ― there is a possibility that development will be completed within this year.

However, experts say vaccine development has a very low probability of success and also takes a long time to get to market.

Kim Woo-joo, a professor for infectious diseases at Korea University in Seoul, said, “If you look at the reports from many experts released so far, only seven percent have been successful in the development of vaccine when it comes to the new infectious diseases.” He continued, “The really important thing is that most cases reached the Phase 3 clinical trials, which are conducted on a large scale, and then just failed.”

Kim said, it is positive that antibodies are formed and neutralizing antibodies have been released in Phase 1 and 2 trials, but we need to see how much the actual protective effect will be in Phase 3.

“Although there have been no reported deaths in Phases 1 or 2 the safety and effectiveness of the new drugs must still be proven,” Kim said.

There are also experts saying even if a vaccine is developed, the actual effect of preventing coronavirus may not be significant and it doesn't guarantee an end to the pandemic.

“It is hard to expect a vaccine that prevents the virus from further spreading completely or reduces mortality,” said Oh Myung-don, chairman of the Central Clinical Committee for Emerging Disease Control, and a renowned infectious diseases physician at Seoul National University Hospital during a recent press conference.

Even if a vaccine is released to the public, the end of the pandemic won't arrive simply by reducing the mortality rate.

Oh said, "Vaccines for viruses that are responsible for respiratory diseases are usually not as effective as those for other viruses."

Among the respiratory organs that viruses such as COVID-19 penetrate, airway mucosa and the nasal cavity are open gateways to our bodies, so there is a limit to preventing respiratory diseases as antibodies formed by vaccines operate internally.