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TOKYO – US drugmaker Pfizer lifted spirits around the world this week with the news that its vaccine candidate was found to be “more than 90% effective in preventing COVID-19.”
Scientists believe it could lead to a victory against the coronavirus, but they caution against premature optimism and want more information before drawing conclusions. Here are five things to know.
What does that mean?
Most vaccines are intended to increase the body’s immune response against a virus, thereby alleviating symptoms such as fever, rather than preventing the actual infection.
Details on the Pfizer candidate remain scant. Experts say that the public should not assume that a vaccine will eliminate the risk of contracting the virus at all.
What technology was incorporated into the vaccine?
The candidate vaccine developed by Pfizer and the German company BioNTech is based on genetic engineering based on messenger RNA. Genetic instructions are injected into human cells so that they assemble something that looks like the coronavirus and allow the body’s immune system to prepare for its invasion.
Traditional vaccines inject a weakened form of a real virus into people. Gene-based vaccines are a rapidly developing field, but they have not yet been used in humans.
How long do the effects last?
This remains to be seen.
The way vaccines work is by inducing a response from the body’s immune system. But the effectiveness of a vaccine decreases over time. Flu vaccines work for only about four months, but that’s enough because the flu season is typically short, three months in winter, said Ko Ichihashi, a professor at Jichi Medical University in Japan.
The coronavirus is more of a problem throughout the year. Outbreaks are constantly occurring somewhere in the world, which means that the virus could enter a region at any time. If the effects of the vaccine are short-lived, people may need to get vaccinated three or four times a year.
Does it work for everyone?
The effects of a virus can differ between populations and viruses also constantly mutate. The coronavirus strains that are spreading in Europe are known to be different from those that have spread in Asia.
Pfizer says its trial involves 43,538 people in the US and other countries, suggesting that the candidate vaccine may be widely effective. Ichihashi says that the current strains of coronavirus probably don’t differ enough to require different vaccines.
Will there be enough supply?
Messenger RNA is a large molecule that is difficult to manufacture and store. A production line can stop due to even a small amount of contamination. Smooth production is not guaranteed in any way.
Japan, the US and the UK have agreements to receive tens of millions of doses of vaccines from Pfizer. The US company is also in talks with Hong Kong and the Philippines to supply the candidate vaccine, according to Airfinity, a scientific information and analysis company.
But countries have aligned other vendors so that any issue with Pfizer or another developer does not mean a complete loss of vaccine availability.
Pfizer alone lacks the capacity to meet the world’s vaccine needs. Other drug manufacturers will continue their own vaccine development and give countries more options.
Other developers now face the high bar set by Pfizer, which far exceeds the 50% efficacy rate required by the U.S. Food and Drug Administration, said Sunao Manabe, president and CEO of Daiichi Sankyo, a pharmacist. Japanese and developer of a coronavirus-like vaccine candidate. Daiichi Sankyo aims to start a clinical trial on his own messenger RNA candidate in March.
“We would like to achieve an efficiency rate as high as Pfizer’s,” Manabe said in an interview.
China and Russia are likely to continue their national vaccine programs. China has promised vaccines to neighboring countries, a campaign that is expected to increase Chinese influence in Asia.
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