The Chinese state-run Global Times claimed on Thursday that inactivated vaccines “should be better” at protecting people “against mutations” of the Chinese coronavirus than messenger RNA (mRNA) vaccines.
“In theory, inactivated vaccines carry all antigens of the virus, so they are able to neutralize a wider coverage of variants. Its efficacy against mutations should be better than the mRNA vaccines, but this requires further evaluation,” a Beijing-based immunologist told the Global Times on July 8 on condition of anonymity.
“Some elderly or vulnerable people, such as allergy suffers, who were hesitant about the two innovative mRNA vaccines available in Singapore are more inclined to go for the [Chinese state-made] CoronaVac — a safer and more traditional choice,” an anonymous Singaporean citizen also allegedly told the Global Times this week.
CoronaVac, also known as Sinovac-CoronaVac, is an inactivated vaccine, meaning it uses a “killed version of the germ that causes a disease” to impart immunity to a recipient.
“Inactivated vaccines usually don’t provide immunity (protection) that’s as strong as live vaccines. So you may need several doses over time (booster shots) in order to get ongoing immunity against diseases,” the U.S. Department of Health and Human Services (HHS) writes on its official website.
According to the HHS, “mRNA vaccines make proteins in order to trigger an immune response. mRNA vaccines have several benefits compared to other types of vaccines, including shorter manufacturing times and, because they do not contain a live virus, no risk of causing disease in the person getting vaccinated.”
According to the Mayo Clinic, a U.S.-based medical research center, mRNA vaccines use “genetically engineered mRNA to give your cells instructions for how to make the S protein found on the surface of the COVID-19 [Chinese corona]virus.”
“After vaccination, your immune cells begin making the S protein pieces and displaying them on cell surfaces. This causes your body to create antibodies. If you later become infected with the COVID-19 [Chinese corona]virus, these antibodies will fight the virus,” the Mayo Clinic writes on its official website.
“After delivering instructions, the mRNA is immediately broken down. It never enters the nucleus of your cells, where your DNA is kept. Both the Pfizer-BioNTech and the Moderna COVID-19 [Chinese coronavirus] vaccines use mRNA,” according to the research center.
Inactivated vaccine technology is well established and has been used since the late 1880s to produce vaccines against various pestilences including “typhoid, [the] plague, and cholera bacilli,” according to a History of Vaccination published by the U.S. National Academy of Sciences. Modern activated vaccines impart immunity against influenza, Hepatitis A, polio, and rabies. The technology used to produce mRNA vaccines is newer than that of inactivated vaccines and therefore less studied. The only mRNA vaccines currently in existence were created in 2020 to impart immunity against the Chinese coronavirus.
The British science journal Nature compared the efficacy of two inactivated coronavirus vaccines developed by Chinese state-run companies, including Sinovac-CoronaVac, and mRNA coronavirus vaccines produced by Western companies in June.
“Both of the approved Chinese vaccines use established technology based on inactivated virus and can be stored at fridge temperatures, which makes them easy to distribute in resource-poor settings,” Nature acknowledged.
“[B]ut these kinds of COVID-19 [Chinese coronavirus] vaccine seem to offer less protection against the disease than do mRNA vaccines such as that made by pharmaceutical company Pfizer in New York City and biotechnology firm BioNTech in Mainz, Germany, and the one made by biotech company Moderna in Cambridge, Massachusetts,” the journal noted.
“Researchers say this could be due to the technology itself. The [inactivated] vaccines use a killed version of SARS-CoV-2 to induce the human body to make antibodies against many regions of the virus,” Nature explained.
“But only some of these antibodies are effective at disabling the virus,” Gagandeep Kang, a virologist at the Christian Medical College in Vellore, India, told the journal.
“Other platforms induce more targeted responses against specific parts of the virus, which might be why they are more effective. The mRNA vaccines encode the ‘spike’ protein that SARS-CoV-2 uses to enter cells, so they trigger high numbers of antibodies that block that protein,” Kang, who also serves as an immunization adviser to the World Health Organization, added.
Sinovac-CoronaVac made international headlines on July 8 for its low efficacy rate, while European health regulators on July 9 announced both Pfizer and Moderna’s mRNA vaccines were linked to “very rare” cases of heart inflammation, which have caused at least five deaths in Europe so far.
“The link with heart inflammation was found only in the vaccines that rely on mRNA technology to train the immune system,” the BBC noted on Friday.
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