The first Pfizer vaccine arrived in Nome.

The COVID-19 vaccine is coming to Nome and the region

How do the COVID vaccines work, who gets it first and what is the new technology behind its development?

With the Pfizer-BioNTech vaccine approved in the U.S. last week and the Moderna vaccine not far behind, an unprecedented vaccination campaign has started across the country. Nome is scheduled to receive its first doses before the end of the week, and although some people remain skeptical of the new vaccine, medical professionals are strongly encouraging those eligible to sign up for the shot.
One of the most widespread suspicions of the new vaccine has been the speed of its development. With less than a year between the start of development and rollout, the new COVID vaccines are shattering previous records of vaccine development, and some wonder whether they’ve been adequately tested.
A big part of the new vaccines’ speed, though, comes from technological advancements that weren’t around when other vaccines were being developed. Both the Pfizer-BioNTech and Moderna vaccines use a method called mRNA, which hugely reduces the time it takes to create new vaccine candidates.
Instead of a live or dead SARS-CoV-2 virus, the new vaccines contain only a snippet of the virus’ genetic code, stored in a molecule similar to DNA called mRNA. The small pieces of mRNA are encased in a bubble of fat molecules to keep them from disintegrating, and those bubbles are suspended in a solution of water, sugar and salt. The mRNA molecules are still very unstable, though, which is why many mRNA vaccines need to be kept at extremely cold temperatures, such as the Pfizer vaccine.
Once the vaccine is injected in a person’s muscle (for most people, the upper arm), muscle cells start reading the mRNA and “translating” it into protein.
Those proteins are the same proteins on the outside of the SARS-CoV-2 virus – essentially the virus’s “signature” – but because they aren’t attached to the rest of the viral machinery, they can’t infect nearby cells.
Instead, they float around until the body’s natural immune system recognizes them as something foreign and musters an immune response. The body then starts producing antibodies – defensive molecules keyed to the specific proteins – to fight off what it sees as an infection.
After two doses of the vaccine, the immune system remembers the virus’ proteins, so that if the actual virus appears, the body can recognize it and fight it off before it starts spreading.
Other vaccines operate on the same general principle, but they use a weakened or incapacitated virus to train the immune system. Getting that process just right to trigger an immune response without starting an infection can be difficult and time-consuming.
Before COVID-19, for example, the vaccine with the fastest development time was the mumps vaccine, which was developed by Maurice Hilleman and licensed in 1967 after four years of work.
To develop that vaccine, Hilleman took a sample of mumps from his own daughter and let it reproduce in chicken embryos, selectively “breeding” it so that it became more infective in chickens, and therefore less infective in humans, in a process called attenuation. That process alone took years, since Hilleman had to weaken the virus so that it wasn’t dangerous to people, but still keep it strong enough so that the human immune system would adequately respond and remember the virus afterward. His final product four years later is the same mumps vaccine most children in the U.S. receive today, combined with the measles and rubella vaccines into the MMR, which was first licensed in 1971.
Today, genetic technology offers a way around the time-consuming attenuation process. Chinese scientists published the novel coronavirus genome in January, and within months biotech companies like BioNTech and Moderna had created potential vaccines using the virus’ mRNA.
Most of the wait between March and now has been for the completion of clinical trials. The Pfizer-BioNTech vaccine has been tested in more than 44,000 people, and independent panels of scientists have found no safety concerns. For Phase III of those trials, about 30,000 people from all over the world volunteered to get a shot. Half of them received the real vaccine, and the other half received a placebo shot that offered no protection. Over the course of three months, researchers kept track of who caught COVID and who didn’t. For both the Pfizer and Moderna vaccines, between 90 and 95 of participants who got sick were in the placebo group, meaning that the vaccine was 90 to 95 percent effective.
Scientists also did bloodwork on the trial participants and found that the vaccine produced a high level of antibodies, even in those participants who ended up getting COVID. The few who did get sick had a strong immune response and very mild symptoms.
Unlike other vaccines that use actual virus, the mRNA vaccines pose no risk of a COVID-19 infection, and no study participants showed any kind of sickness or dangerous side effects from the vaccine.
Those who did have side effects experienced soreness in their arm, and sometimes a light fever, which is the body’s response to what it thinks is an infection, but is actually just the viral protein.
So why haven’t we heard about this new mRNA technology before? Mostly because there wasn’t a disease to use it on.
Many viruses, such as measles and polio, have had effective vaccines for years, and there was no reason to develop a new vaccine when the old ones worked just fine.
Other viruses, like HIV, mutate extremely quickly. HIV can mutate into multiple strains in just one person – so the basic vaccine principle of “training” the immune system to recognize the virus doesn’t work as readily.
But the novel coronavirus that causes the sickness called COVID-19 was a perfect candidate for the new technology, because no previous vaccine existed, the virus doesn’t appear to mutate extremely quickly and there is enough interest in a vaccine to make it financially feasible.
That’s where Operation Warp Speed entered the picture, the $14 billion investment from the federal government to pay for the development and distribution of a vaccine. The funding essentially guaranteed that biotech and pharmaceutical companies would not lose money on vaccine development, incentivizing them to commit all their resources to producing a safe, effective vaccine.
Other countries implemented similar financial incentives, promising to purchase doses of vaccine before they had been approved. While it represented some financial risk for the governments involved – none of the vaccines were guaranteed to be safe and effective from the outset – it allowed for much more rapid testing.
That combination of new technology and financial incentives had never existed before 2020 and explains why the new COVID vaccines were able to be developed, tested and manufactured so quickly.
There are still some important things about the new vaccines that need additional testing. The time intervals between the first and second doses, for example – 21 days for Pfizer-BioNTech and 28 days for Moderna– are for now very strict, because their effectiveness hasn’t been proven with any other interval.
The Moderna vaccine would likely work fine if the second does is delivered 29 days later instead of 28, but proving that in clinical trials would take months.
So, for the initial rollout, doctors are making sure that the second doses are administered exactly according to the schedules used in the fall’s clinical trials.
The most important unknown is how long immunity from the vaccine will last. Since both the new vaccines tend to elicit a stronger immune response than a real coronavirus infection, many scientists think that immunity from the vaccine will last longer than immunity from infection. But the only way to know that for sure is to vaccinate a large enough share of the population – about 70 to 75 percent – and wait for case numbers, hospitalization rates and death rates to go down.
In the meantime, with widespread vaccination still months away and thousands dying every single day, it appears that things are likely to get worse before they get better. Health officials continue to promote mask wearing, social distancing and hand washing as steps to curb further spread of the disease.

 

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