When scientists began the quest for a COVID-19 vaccine in early 2020, they warned us not to get our hopes up. Vaccine development is a notoriously long process, taking years before they may or may not make the cut. Before this past year, the fastest vaccine that had ever been developed and approved was a mumps vaccine, which took four years in the 1960s.
Nonetheless, by December 2020, pharmaceutical companies began announcing promising results in large-scale trials. Later that month, the Pfizer-BioNTech vaccine became the first fully tested immunization vaccine to be approved for emergency use. Finally, there seemed to be light at the end of the tunnel. Given that the world has been holding out for a cure, here are some of the facts you need to know:
The Pfizer-BioNTech vaccine uses new mRNA technology, putting it on the forefront of modern medicine. Trials in patients sixteen or older have a 95% efficacy rate, though the vaccine’s duration of protection is unknown. This jab is given in two doses, twenty one days apart. However, this vaccine requires ultra-cold chain-storage in a minus seventy degree Celsius freezer throughout transportation and storage, making it logistically difficult to manage.
The Moderna vaccine also uses mRNA technology to immunize recipients, and has an efficacy rate of 94.1%. Like the Pfizer-BioNTech vaccine, it requires two doses, spaced twenty eight days apart. If needed, a second dose can be administered up to six weeks after the first dose. Trials have only been conducted in adults. Unlike the Pfizer vaccine, the Moderna vaccine only needs to be stored at minus twenty degrees Celsius, the same temperature as in a normal freezer.
CoronaVac, the vaccine produced by pharmaceutical company Sinovac Biotech, uses the more traditional inactivated vaccine technology. Although Phase I and II trials initially reported 78% efficacy, later trials in Brazil reported only 50.4%, which is barely enough to pass the World Health Organization’s minimum efficacy threshold. One of the Sinovac vaccine’s main advantages is that it only needs to be stored at two to eight degrees Celsius, so it would be more useful in developing countries that may not be able to store large quantities of vaccines at very cold temperatures.
Results from clinical trials of the Novavax vaccine show that the protein subunit vaccine has a 90% efficacy rate. Trials also show that this vaccine is effective against the B117 United Kingdom variant. Notably, 27% of the participants in the phase III trials were over sixty five. Recipients should expect two doses, three weeks apart, while further studies are being done to study the efficacy of only one dose or two doses with longer time between.
The Oxford-AstraZeneca vaccine uses viral vector technology to protect recipients. It uses a modified, weakened version of the common cold virus (adenovirus) from chimpanzees to deliver a DNA strand that codes for spike proteins in our cells to create immunity, and has 70% efficacy. Interestingly, an earlier study published by the Oxford-AstraZeneca team shows that tweaking the dose can increase the vaccine’s efficacy. In one trial, recipients were accidentally only given a half-dose during their first injection, but this turned out to be a serendipitous mistake - while the efficacy of two full doses proved 59% effective, the efficacy of the half-dose followed by a full dose increased to 90%. This jab is less expensive and easier to store than the Moderna and Pfizer varieties meaning that it can more easily reach every corner of the world.
Starting earlier this month, Massachusetts is administering free Pfizer and Moderna vaccines to anyone age seventy five and above or in the Phase I priority group (healthcare and essential workers). The vaccine is available at hospitals, pharmacies, and other healthcare centers around the state. Even Fenway Park has been converted into a distribution center! Education workers, whether teaching staff, administration, or otherwise, can expect to receive a vaccine from the Massachusetts government starting in April, 2021. After that, the general public (including older students) will be offered the vaccine.