The ‘best’ vaccines in the world could soon reach poor countries | India News
In the 6 months since Covid vaccines became available, those based on mRNA technology have obtained the best ratings. So far, there are only two, manufactured by Pfizer Y Modern – and both show an efficiency of 95%.
Other types of vaccines are usually 80% effective or less. This difference affects not only the protection you receive as an individual, but also the protection available to the ‘herd’ or society. With a better vaccine, a country can achieve “herd immunity” faster if fewer people are vaccinated.
But mRNA vaccines are still limited to the rich world. This is partly because the supply is limited and those countries placed their orders first. Another reason is that these vaccines spoil if they are not stored in extremely cold temperatures. The Pfizer injection initially required storage at -80 ° C. Poor countries could not afford to buy specialty freezers in bulk.
A fragile molecule
Why do mRNA vaccines need ultra-cold storage? It’s because its main ingredient, mRNA (messenger RNA), is extremely fragile. “(It’s) really easy to destroy, and that’s because there are many, many enzymes that will just break it down,” writes Selena Simmons-Duffin in NPR.
Ultra cold temperatures prevent it. “The lower the temperatures, the slower the molecular movements and the lower the possibility of harmful reactions,” says Maya Wei-Haas in the National Geographic.
The key ingredient in the vaccine is called a “messenger” because it carries instructions for its cells to become part of the Covid virus. Your immune system learns to recognize this part and deal with the real virus.
If the mRNA is broken, the message is lost. “Just one cut in the mRNA strand can be enough to lose function,” Wei-Haas quotes a scientist.
Second generation mRNA
Last year, mRNA vaccine manufacturers were in a rush to get the vaccines out, even if deep freezers were needed to keep them stable. “Our top priority was to rapidly develop a safe and effective vaccine,” said Ugur Sahin, CEO of Pfizer’s vaccine partner. BioNTech, saying. But now they are focusing on updated vaccines that are easier to store and distribute.
In the next few days, a third mRNA vaccine could arrive, writes Carl Zimmer in The New York Times. Manufactured by the German company Cure-Vac, it has caught the world’s attention because it is stable at 5 ° C for 3 months and can be left at room temperature for 24 hours.
The vaccine has been tested on 40,000 volunteers in Europe and Latin America, says Zimmer, and “CureVac is about to announce the results.” If successful, it could reach low- and middle-income countries.
Meanwhile, BioNTech announced on May 4 that it is “working towards approval” of its updated mRNA vaccine that can be safely stored at 2 ° C-8 ° C for up to 6 months.
Moderna began a trial of its next-generation vaccine, called mRNA-1283, in March.
15. Executive Director Stéphane Bancel said they expect the new vaccine to be “stable in the refrigerator” and that it could “facilitate easier distribution and administration, potentially even for developing countries.”
First generation surprise
The first mRNA vaccines from Pfizer and Moderna also turned out to be much more resistant than initially thought. Pfizer’s -80 ° C requirement is old news now. Long-term studies showed that the vaccine kept well between -25 ° C and -15 ° C for up to two weeks. The US Food and Drug Administration approved this new storage tip on February 25th.
Moderna now claims that its existing vaccine (mRNA-1273) can be kept at 2 ° C-8 ° C for up to three months. Initially, it was considered safe at this temperature for only one month.