Covid Vaccines Confer No Sterilizing Immunity
This is very important for people to understand!
The new Covid vaccines are NOT like what most people imagine a vaccine to be! They will be nothing at all like the measles or smallpox vaccines that actually prevent infection.
This is a topic I've been discussing since July when the initial vaccine animal studies went up on the pre-print servers. None of the current vaccine candidates confers "sterilizing immunity" to the SarsCoV2 virus!
A non-sterilizing vaccinated means that a person can:
Still get infected with the virus
Can absolutely infect others around them
Can still get sick and even die.
The vaccines DO offer "disease immunity" in which the virus will be prevented from jumping to the bloodstream due to the production of neutralizing antibodies. This reduces the chance the disease will have severe effects on the vascular system and major internal organs.
This means your chances of developing severe illness and death are significantly reduced, but not eliminated. You can still get sick and it can still develop into pneumonia and you can still die just like with the flu. But severe illness will be significantly reduced for most people who get vaccinated.
From Moderna’s Chief Medical Officer
Here's a quote from Dr. Tal Zaks, Moderna’s Chief Medical Officer -
“I think we need to be careful, as we get vaccinated, not to over-interpret the results. When we start the deployment of this vaccine, we will not have sufficient concrete data to prove that this vaccine reduces transmission.”
This non-sterilizing effect has been demonstrated in the Moderna, Pfizer, and AstraZeneca vaccines and is likely a feature of all 1st-generation Covid vaccines.
Implications for the Future
This means that the use of masks, distancing, limited closures, and other mitigation efforts will STILL be required long after the vaccines are introduced. This will be the case at least until we exceed 70%-to-80% vaccine compliance and may still be required for those over 60 well after full vaccine compliance.
If we drop all mitigation efforts, even with full vaccine compliance, the virus will go fully endemic and almost everyone will catch Covid-19 once or twice a year.
In such a scenario, Covid will be as widespread as the common cold but kill like seasonal influenza. The average person gets 3 colds a year with over a 1-billion colds a year in the US versus only about 30M to 50M cases of seasonal influenza.
Because Covid vastly more infectious than seasonal influenza, we should expect 6x to 10x as many cases of Covid as the flu, but with a death rate comparable to the flu.
Even after full vaccine compliance (80% plus), with a fully re-opened economy and no mitigation measures, Covid-19 will likely remain the 3rd leading cause of death in the US after heart disease and cancer with an annual death toll of >300k deaths per year.
This is why maintaining mitigation measures like mask usage, distance, reduced social density may be necessary for the next several years. Unfortunately, there will likely be a strong political push to drop all mitigation measures shortly after the vaccine is widely available.
In a scenario where there’s a 50% vaccination rate and no mitigation measures, the death rate could easily be 2x-to-3x higher as it becomes increasingly difficult for those unwilling to take the vaccine to avoid infection...but without any of the protections of the vaccine!
If we drop mitigation measures with only half the population vaccinated, then by this time next year, the epidemic could be at levels vastly above where we are today!
Widespread support for vaccinations will be crucial for the economy and society to resume to any sort of reasonable level. And because the SarsCoV2 virus is so contagious, a vaccine compliance level of 80% will be needed before we see a full return to more normal levels of social interaction.
It will be important for the broad population to understand exactly how these vaccines will and will not work. And to understand the distinctions and implications of concepts like “sterilizing immunity” and “disease immunity” and “immune duration”.
All these distinctions are VERY important for people to understand to push back on popular pressure to drop mitigation efforts.
Links to References:
These observations suggest that we cannot assume COVID-19 vaccines, even if shown to be effective in reducing severity of disease, will reduce virus transmission to a comparable degree. The notion that COVID-19-vaccine-induced population immunity will allow a return to pre-COVID-19 “normalcy” might be based on illusory assumptions.
Intramuscular dosing of ChAd-SARS-CoV-2-S induces robust systemic humoral and cell-mediated immune responses and protects against lung infection, inflammation, and pathology but does not confer sterilizing immunity, as evidenced by detection of viral RNA and induction of anti-nucleoprotein antibodies after SARS-CoV-2 challenge
Vincent Munster, who leads the team that conducted that study, said a vaccine that could mitigate the severity of the Covid-19 pandemic would still be a significant contribution in a world struggling to co-exist with a dangerous new virus.
Michael Mina, an infectious diseases epidemiologist at Harvard’s T.H. Chan School of Public Health, thinks achieving sterilizing immunity with a vaccine will not be possible for Covid-19. Experience with human coronaviruses — and with multiple pathogens that cause colds — shows immunity that develops after infection with respiratory tract infections is not lifelong. In some cases, the duration is measured in months, not years.
“If [infection with] natural coronaviruses doesn’t do it, I don’t think that we should necessarily expect or have the anticipation that we’ll be able to get there with the vaccine,” said Mina, who is also associate medical director of clinical microbiology at Boston’s Brigham and Women’s Hospital.
“Everyone thinks COVID-19 will go away with a vaccine,” said Dr. William Haseltine, chair and president of Access Health International, a foundation that advocates for affordable care.
But the trials, which will study 30,000 to 60,000 volunteers, will be too short in duration and too small in size to prove that the vaccines will prevent what people fear most — being hospitalized or dying — by the time the first vaccine makers file for emergency authorization, expected to occur later this year, Haseltine said.
Viral loads in BAL fluid and lung tissue of vaccinated animals were significantly reduced, 162 suggesting that vaccination prevents virus replication in the lower respiratory tract. Despite this 163 marked difference in virus replication in the lungs, reduction in viral shedding from the nose was 164 not observed
"We think it is a serious omission to ignore the mucosal immune response to SARS-CoV-2, given its initial sites of infection," said Michael W. Russell, PhD, emeritus professor, Department of Microbiology and Immunology in the Jacobs School of Medicine and Biomedical Sciences at UB, and senior author on the paper. "Clearly the response of the systemic immunoglobulin G antibody [the most abundant circulating antibody] is important—we do not deny that—but on its own it is insufficient."
Russell noted that naturally, the initial focus of research on the disease was on cases of severe disease when the virus descends into the lower respiratory tract, especially the lungs, where the cellular immune responses exacerbate the inflammation rather than fight the infection.
But since the upper respiratory tract, including the nose, tonsils and adenoids are the initial point of infection for the SARS-CoV-2 virus, the immune responses that are triggered there are of special interest.
About the author:
I am a scientist with 20+ years in the biotech industry. I currently work as a consultant with companies involved in developing molecular diagnostics platforms, including some of the key testing platforms used to detect the SarsCoV2 virus.
So I bring an insider’s perspective that is scientifically oriented but directed to a general audience trying to make sense of the conflicting stories surrounding the Covid pandemic.
To learn more: https://www.linkedin.com/in/dalewharrison/
If you found this article useful, please sign up by hitting the “Subscribe Now” button below or share it with a friend…