Four things you should know about the new crown vaccination

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The new coronary pneumonia vaccine is expected to become the fastest vaccine in the development process in recent years.

As the COVID-19 vaccine developed by multinational pharmaceutical companies enters late-stage trials, countries are beginning to prepare vaccination plans.

Among them, several vaccines jointly developed by the American pharmaceutical company Moderna, Pfizer Pharmaceuticals, and Germany’s BioNTech, and several vaccines from China’s Zhongwei Biotechnology Co., Ltd. have entered the third trial stage. Volunteers are injected with vaccines to test whether they can be effectively cultured in humans. immunity.

Pfizer expects to provide about 50 million doses of the vaccine this year, with production rising to 1.3 billion next year. But there are still several issues that need to be addressed before a mass vaccination program can be launched.

How effective are vaccines in preventing COVID-19?

Preliminary data released by Moderna earlier showed that its newly developed new crown vaccine can achieve nearly 95% efficacy; in addition, the vaccine jointly developed by Pfizer and BioNTech is reported to be able to achieve 90% efficacy.

It is widely believed that the test results of both vaccines are better than expected, but this number does not necessarily represent the efficiency of the vaccine in the actual environment, because these two numbers only reflect the “efficiency” in a controlled environment in the laboratory ” (efficacy), rather than “effectiveness” as it is widely used.

According to the Center for Disease Control and Prevention, when a vaccine is in the trial phase, people are first selected in a more rigorous way, who usually do not have the severe disease themselves. or other health conditions, ensuring that researchers can accurately measure vaccine efficacy independent of other factors. The numbers from Moderna, Pfizer, and BioNTech refer to the results of vaccine testing under these circumstances.

In the practical application of vaccines, the “efficacy” of vaccines may be affected by factors such as the age, physical condition, and disease of the inoculated subjects. Vaccine research and development companies will try to expand the test scale when conducting human testing to know the efficacy of the vaccine on different groups, but this cannot fully simulate the actual environment.

video caption, Preliminary data show that the new crown vaccine developed by Pfizer and the German pharmaceutical company BioNTech is 90% effective.

How long are vaccines valid for?

When a person develops antibodies through contracting COVID-19 or being vaccinated, immunity to the virus can last, according to preliminary research from the La Jolla Institute of Immunology. For several years, the public will be able to vaccinate more people without repeated vaccinations in a short period and accelerate the development of immunity to the new coronavirus pneumonia virus in the population of various countries.

The results of this study still need further confirmation, but the New York Times said other similar studies had similar findings. Among them, the University of Washington discovered earlier that after a person is infected with the new coronary pneumonia virus or vaccinated, it will develop a “memory cell” that survives in the body for at least three months, allowing these people’s immune systems to stay at any time. Produce antibodies that can fight the new coronavirus.

The New York Times quoted Jennifer Gommerman, another University of Toronto researcher who has conducted similar studies, as saying that a small number of patients with new coronary pneumonia will only have immunity to the virus for a short time after recovery, but She believes these people can still have long-term immunity to the virus after being vaccinated.

Why do different vaccines require different storage environments?

The current Covid-19 vaccine needs to be stored at a very low temperature like other vaccines to ensure it does not spoil.

For example, Pfizer and BioNTech’s COVID-19 vaccines reportedly need to be stored at minus 70 degrees Celsius, but medical clinics usually don’t have refrigeration equipment that can reach this temperature, so the two companies plan to ship them in cooler boxes. Load vaccine and keep cool on dry ice. Medical clinic staff needs to replenish dry ice every five days, which keeps the vaccine for about two weeks.

A key advantage of Moderna’s vaccine is that it does not require ultra-low temperature storage like Pfizer’s vaccine, which makes transportation, distribution easier, and increases the flexibility of vaccination schedules. Moderna hopes it will be stable for 30 days at normal refrigerator temperatures of 2 to 8 degrees Celsius, and up to six months at minus 20 degrees Celsius.

The American Journal of Science pointed out that both vaccines use messenger ribonucleic acid (mRNA) to trigger human cells to develop immunity to the new coronavirus. But this messenger ribonucleic acid is very fragile, and if it encounters a slightly higher temperature, it will split and fail.

To make sure the messenger RNA is less likely to fail, the researchers inject it into a protective layer of lipid nanoparticles. This lipid particle is naturally broken down in the body so that it does not accumulate in the liver after it is injected into the human body with the vaccine.

With the development of new coronary pneumonia vaccines, many companies continue to develop vaccines that can be stored close to room temperature, which is convenient for storage and transportation. Among them, the German company CureVac announced in October that the vaccine it developed only needs to be stored in an environment of 5 degrees Celsius and can still be valid for three months.

The storage environment of vaccines has a great impact on the preparation of vaccination plans by governments. If COVID-19 vaccines must be stored in ultra-cold environments and transported to remote areas or developing countries where electricity and dry ice supplies may not be sufficient, it will become difficult.

How much does it cost to buy vaccines?

Various pharmaceutical companies currently price the new coronary pneumonia vaccine at different prices. The currently known prices range from the British pharmaceutical company AstraZeneca (AstraZeneca) about three to four US dollars apiece, to Moderna (Moderna) $50 to $60. The two vaccines consist of different courses of treatment.

One focus of discussions on vaccine pricing is how to share the cost of purchasing vaccines between rich and poor countries.

Bill Gates, the founder of Microsoft and now co-chair of the Bill & Melinda Gates Foundation, was quoted by the Financial Times as saying he believed countries should The costs are shared in three tiers: rich countries pay the most, middle-income countries pay a little, and poor countries pay only a small amount.

At present, 171 economies around the world have joined the vaccine guarantee mechanism led by the World Health Organization, including 79 high-income countries including China, but the United States has not participated.

To reach the goal of providing 2 billion doses of vaccines globally by 2021, these high-income countries need to prepay for vaccines. According to the World Health Organization, as of September, countries around the world have agreed to provide about US$1 billion in funding for the plan, including US$752 million in the UK, US$332 million in Canada, and US$117 million in Germany.

It is currently unknown how much money China will invest in the plan. The Chinese government has repeatedly pointed out that vaccines made in China will be “global public goods” and will give priority to providing vaccines to Laos, Myanmar, Thailand, Vietnam, and other Mekong countries, but no detailed plan has been given. 

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