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[Japan] U.S. vaccines look promising, but crucial questions remain (nationthailand.com)

[Japan] U.S. vaccines look promising, but crucial questions remain

Nov 25. 2020(The Yomiuri Shimbun) 

By Sho Funakoshi and Taizan Emura
Yomiuri Shimbun/The Japan News/ANN

Two major U.S. pharmaceutical companies have released promising results from large-scale clinical trials of novel coronavirus vaccines. These companies will soon submit applications to the U.S. government to receive emergency use authorization for these highly effective vaccines.

Vaccinations in Japan could start as soon as the first half of 2021, but question marks remain over whether the nation will be ready to roll out the shots and whether the vaccines could have side effects.

■ Over 90% effective

Anthony Fauci, director of the U.S. National Institute of Allergy and Infectious Diseases and a member of the U.S. government’s coronavirus task force, was bullish about the trial results. “We have two vaccines that are really quite effective, so I think this is a really strong step forward to where we want to be about getting control of this outbreak,” Fauci said during an interview with U.S. network NBC on Nov. 16.

On Nov. 18, U.S. pharmaceutical giant Pfizer Inc. announced the preliminary results of a clinical trial involving about 43,500 people. About half were given the newly developed vaccine, and the rest were given a placebo. All were observed for a month to check who developed coronavirus symptoms.

Only eight of the group who received the vaccine showed symptoms, but 162 in the placebo group did. This 95% effective vaccine could reduce the number of people who develop symptoms to just one-twentieth of what it is now. U.S. biotechnology company Moderna, Inc. also announced on Nov. 16 that its vaccine was 94.5% effective.

Influenza vaccines are said to be 30% to 50% effective in preventing people from catching the flu. The U.S. Food and Drug Administration issued guidance that stipulated a coronavirus vaccine would be considered effective if it prevented the disease or decreased its severity in 50% of people who got vaccinated. The development of two vaccines that are more than 90% effective stunned many experts.

“There is a strong likelihood this outbreak can be brought under control to some degree,” said Keio University Prof. Akihiko Yoshimura, an immunology expert.

■ No room for complacency

Both vaccines are so-called genetic vaccines that inject a modified part of the coronavirus’ genetic code. This technique has the advantage of developing vaccines more quickly than conventional methods; a process that would normally take several years has this time taken less than one year.

However, it remains unclear how long these vaccines will remain effective and if their impact will vary between individuals. It also is unknown if the vaccine will need to be given each year like a flu shot, or if one or two doses will offer a lifetime of protection, like the measles vaccination does.

■ Prevention still crucial

Potential side effects triggered by the vaccines also need to be closely checked.

Both companies’ vaccines involved two doses given about three or four weeks apart. After receiving the second jab, the proportion of people who felt lethargic or complained of muscle pain ranged from about 2% up to about 10%. Although no severe side effects were reported, University of Tokyo Prof. Ken Ishii warned about getting complacent.

“Generally speaking, vaccines that give stronger immunity also have stronger side effects,” said Ishii, a vaccine science expert. “We must carefully pay attention to any information about side effects and ensure that people who get vaccinated are aware of the risks.”

Furthermore, if a vaccine cannot completely prevent an infection and a vaccinated person stops taking precautions, they could catch the virus and spread it to people around them. Steps such as wearing a mask and avoiding the three Cs — closed spaces, crowded places and close-contact settings — likely will remain essential for the foreseeable future.