This morning, two large-scale clinical trials for vaccines against COVID-19 began. The first is from Moderna in collaboration with the National Institutes of Health. It has 30,000 participants throughout our country. Pfizer is conducting the other with 30,000 members at 120 global sites. In either study, half of the individuals will receive the vaccine and the other half will get a placebo.
According to Dr. Anthony Fauci, director of the National Institute of Allergy and Infectious Diseases, the US hasn’t ever developed a vaccine this fast, making this a “truly historic event in the history of vaccinology.” Dr. Fauci estimates that the effectiveness of the Moderna vaccine could be known as soon as November or December, maybe even earlier. Pfizer officials are hoping to be able to seek regulatory approval by October.
Both vaccines involve two doses given several weeks apart. Afterward, researchers have to wait to see whether people get infected or sick from the virus. The hope is that people who received the vaccine will experience fewer infections or less severe episodes of COVID-19. According to Dr. Fauci, to demonstrate the vaccine is 60% effective, there could only be around 150 infections in the 30,000 people.
Not only is immediate protection a concern when developing a vaccine, but so is the long-term benefit. Typically, vaccine-makers learn this during a second-phase of studies that involve hundreds of patients and take months or years. Due to the necessity of producing a vaccine for COVID-19 quickly, the length of trial phases is being reduced. So, while the vaccine is being proven safe and, hopefully, effective, the lasting impacts most likely won’t be understood before it becoming available.
Experts are estimating that the immunity from the vaccine won’t be lifelong given what is known about other respiratory viruses and evolving data on the length of time antibodies to the virus are lasting in those who’ve recovered from it. As of right now, based on the available information about antibodies, the period is at least a few months. The goal is to have the COVID-19 vaccine have at least the same length of protection as the seasonal flu, which is roughly about a year.
As scientists are making remarkable progress in vaccine development, officials are agreeing that test results are taking too long to come back. Since testing is considered a critical element in understanding and controlling the spread of the virus, this is troubling. The problem is that there’s a shortage of supplies and backlog of tests to be done, causing the results to be virtually useless. By the time a person gets the outcome, if they’re positive, they most likely have spread the virus to many others.
The federal government said it’s willing to pay up to $7.6 million to the testing company Hologic to help with the problem. The money is for them to increase the number of tests their machines can run. The goal is to be able to do two million tests per month. The company says that the amplified amount won’t be feasible until next January.
Until then, state and local governments are trying to find a different solution to improve the number of tests being done. One method that is being looked at is pooled testing. Instead of running each person’s test individually, the laboratories could run small groups of tests all at once. If the results of a group test come back negative, then everyone in that group is cleared. If the results are positive, then each sample would need to be rerun one at a time. The good news is the retest doesn’t require another sample from each members of the group because there is usually enough of a person’s original sample left that the second test can be done using that.
Experts point out that it’s vital for the number of people in a group to remain small. The thought is that if the size of the pool increases too much, the test may decrease in sensitivity, which means that cases in which patients have a low viral load could be missed. Low viral loads usually occur very early or late in an infection.
Pooled testing was first used in the 1940s as a way to screen World War II draftees for syphilis. Until recently, it was mainly used by public health labs that needed an inexpensive way to screen thousands of samples for sexually transmitted diseases because they use expensive chemicals. The Food and Drug Administration approved the method for COVID-19 in the past few weeks. According to Dr. Deborah Birx, the White House Coronavirus Task Force Coordinator, “We’re really working to increase pooling. We know that can dramatically increase our throughput.”