Covid-19 messenger RNA vaccines are being updated. The new enhanced footage rolling out across the US and Europe this week is specifically tailored to the Omicron variants currently circulating. Health officials say they will better protect newer versions of SARS-CoV-2 than previous shots, which were designed to target the virus first detected late. 2019.
Since its appearance, the coronavirus has been constantly changing. These mutations have allowed it to spread more easily and better avoid the immune system response caused by the original vaccine and booster. Although Omicron and its subvariables are the easiest to transmit, Our vaccines are still the same.
“We’re basically trying to catch up with a virus that’s constantly evolving,” said Ross McKinney, chief scientific officer at the Association of American Medical Colleges. “And while we cannot predict the future, the hope is that the next variant will be a fork of BA.4 or BA.5. So having antibodies that protect you against that would be very helpful.”
Both BA.4 and BA.5 are subvariables of Omicron. As of September 3, BA.5 accounted for about 88.6% of all Covid-19 cases in the United States, while BA.4 accounted for 2.8%, According to the Centers for Disease Control and Prevention. Meanwhile, a new descendant of BA.4, called BA.4.6, now represents about 8.4% of cases.
Developed separately by Moderna and Pfizer, the new US formulations target the ancestral virus strains BA.4 and BA.5. Called dual-value vaccines, they contain two pieces of messenger RNA that instruct the body’s cells to make a specific “spike” protein of the original virus strain and of those two sub-variants. . The mutant proteins of BA.4 and BA.5 are identical, but dozens of mutations in the protein make it easier for them to overcome antibodies against disease caused by vaccines or previous infections, allowing them to enter human cells.
“Over time, this virus has evolved, so it looks less and less like the virus that has emerged,” said Robert Schooley, professor of infectious diseases at the University of California, San Diego School of Medicine. in human populations. “If our vaccine continues to look like the older variants, we will stimulate the human immune system to recognize those variants, but not the new ones.”
On August 31, Food and Drug Administration emergency authorization for both Moderna and Pfizer-BioNTech specific variant boosters. After that, CDC confirmed the photos for US residents. Meanwhile, European Health Agency and UK’s health regulator approved a bivalent version targeting the original virus and BA.1, variant Omicron became dominant last winter.
Currently, anyone 12 years of age or older can receive a new two-chemotherapy booster shot if they already had an older booster or their main series of vaccines. (That means two doses of Moderna, Pfizer, AstraZeneca, or Novavax vaccine, or one dose of Johnson & Johnson vaccine.) CDC recommends a booster shot at least two months after the previous dose of vaccine. People who have recently taken Covid-19 can delay their booster dose by three months from the start of their symptoms, According to CDC.
