Reader Simon sent me a link to this free paper about coronavirus vaccines written by several researchers, including Anthony Fauci (“senior author” means “last author”, and the convention that this spot is occupied by the Boss or lab head). It’s a useful summary of where we are, which other vaccines are coming, and what we don’t know, and is understandable by the layperson. (Here’s a link to one term you might not know: “mucosal immunity“, while “parenterally” refers to medicines taken outside the digestive tract, usually through injection.)
Click on the screenshot to read:
There’s a useful table of vaccines already used compared to those in development. Of the five remaining vaccines, three involve viruses: mostly inactivated viruses that can’t replicate but can produce the spike protein that activates your antibodies, while two others involve injecting spike proteins themselves, made in insect cells. Click to enlarge:
Here’s a figure I’ve posted before showing the protection you get from the two vaccines in use in America now: the Pfizer/BioNTech and Moderna formulations.
Note that you’ve already gotten substantial protection before you get to the second jab. For both vaccines the efficacy (the reduction in the chance you’ll catch the virus if exposed) is about 95%.
The paper raises several concerns about the vaccines and people’s willingness to take them.
A.) What are the side effects? Monitoring of those injected has only taken place for several months, and there may be long-term effects we don’t know about. The authors note, though, that some of the vaccinated would have had stuff like cancer and heart attacks anyway—effects having nothing to do with the injection. The frequencies of such incidents and diseases need to be compared to those in unvaccinated groups or base rates already known.
B.) We don’t know the efficacy in some important groups, including “children, pregnant women, individuals with underlying illnesses, and those taking medications that might influence the immune response to a disease.”
C.) The duration of protection provided by the vaccines. We know that the efficacy of flu vaccines wanes substantially between six months and a year after injection. Will we have to get yearly injections of coronavirus vaccines as we do with flu shots? Of course they will continue developing vaccines, so they will get better over time.
D.) How well do the vaccines protect against (asymptomatic) infection and transmission of the virus? We should have the answer to this question in a while, and the authors consider this the most important unknown in trying to stem the pandemic. If after injection you can get infected and not show symptoms, as well as transmit the virus, this will dramatically curtail efforts to stop the pandemic cold, and mandate different strategies, like testing those already injected.
And a paragraph from the paper, which is disturbing given that roughly half of Americans plan to get vaccinated. That is INSANE! Tell your worried friends to get their jabs, as it’s better than getting coronavirus.
The point made is that the vaccines currently in use don’t provide immunity in the mucosal membranes (as in the nose), while polio vaccine did bestow that immunity, but only if made with live weakened virus. (Current flu vaccines don’t provide it either.) Active immunity in the mucosa kills the virus in the respiratory system before it has a chance to get into the blood. The coronavirus vaccines now available don’t seem to provide mucosal immunity and, as the authors say, we need vaccines that will do that. A summary:
Given that recent polling suggests that only 40% to 60% of people in the United States are currently planning to get vaccinated, it is conceivable that without some impact on transmission, the virus will continue to circulate, infect, and cause serious disease in certain segments of the unvaccinated population. Administration of parenterally administered vaccines alone typically does not result in potent mucosal immunity that might interrupt infection or transmission. In the case of poliovirus, induction of mucosal immunity through vaccination with the live attenuated oral polio vaccine, in contrast to the parenterally administered inactivated vaccine, was thought to have played a critical role in interruption of transmission and control of poliovirus epidemics. For these reasons, additional data regarding protection from infection should be generated as soon as possible. If these vaccines do not provide durable, high levels of protection from infection, and do not drive the prevalence of virus in the community to near zero, a thorough analysis of shedding and transmission will need to be done through additional study. Armed with such data, public health officials can make decisions regarding prioritization of populations to receive the vaccine, and researchers could potentially improve upon the first wave of vaccines.