COVID Re-infections and the Vaccine
Limited Duration Immunity has Vaccine Implications
The implications of re-infection on vaccines is a significant issue. The viral-vector vaccines from AstraZeneca and Johnson & Johnson will likely be usable only once.
These viral-vector vaccines rely on an engineered active monkey adenovirus, that once injected, will infect host (patient) cells and insert the RNA instructions for the patient’s own cells to manufacture copies of the SarsCoV2 spike-protein.
The vaccine-induced production of SarsCoV2 spike-proteins then induces a host immune response leading to the production of antibodies in the bloodstream capable of neutralizing the SarsCoV2 virus upon later infection.
But the injection of the adenovirus also induces a separate vector-response. An immune response directed against the adenovirus carrier. Future vaccinations with any of the viral-vectors vaccines will be ineffective as the viral-vector will be neutralized before being able to reach and infect host cells.
Essentially, your own immune system will destroy the vaccine before it can work!
Vaccine boosters will likely be required every 6-12 months indefinitely given the short duration of neutralizing antibodies in the bloodstream (3-6 months) and the uncertainty of the effectiveness of long-term t-cell / b-cell immune memory.
Based on recent work out of the La Jolla Institute for Immunology, some people showed high antibody levels up to 8-months after infection, but others exhibited only a short-lived antibody response. So the immune response to the virus seems quite variable and the researchers were not able to identify any predictors for when a patient would exhibit shorter or longer immune duration.
Due to such variability in immune-response, rather than a fixed time-window for getting a vaccine booster, people will likely need to test themselves monthly for antibody levels (with a simple home test-strip) and schedule a vaccine booster when antibody levels drop below a prescribed level.
And in such a case, the only remaining vaccine option would be one of the mRNA vaccines such as the Pfizer or Moderna candidates. This is the importance of having multiple vaccine candidates based on different vaccine technologies approved and available.
Addendum: The Johnson & Johnson vaccine is built on a rarer adenovirus subtype Ad26. The AstraZeneca vaccine is built on the Ad5 subtype. So it should be possible to still rely on the other viral-vector vaccine for subsequent boosters.
A Covid Researcher Who Re-Infected Himself
Below is an excerpt from an article about the Russian research Dr. Chepurnov and his experience with Covid re-infection.
Prof Chepurnov, who says he first caught coronavirus on a skiing holiday in Italy, became famous in Russia when he used himself as a guinea pig.
He said his personal experiment showed he had antibodies for three months after his first infection, after which they reduced.
He then deliberately exposed himself to Covid patients while not wearing protective gear - and caught it again.
The second bout was worse and he ended up in the hospital with double-pneumonia but has since recovered, he said.
The experiment led him to conclude hopes of "herd immunity" in a population are "overblown" and even that vaccines relying on antibodies might only work for a few months.
He said: "We need a vaccine that can be used multiple times, a recombinant vaccine will not suit.
"Once injected with an adenoviral vector-based vaccine, we won't be able to repeat it because the immunity against the adenoviral carrier will keep interfering."
Link to article:
Additional Scientific References
Excellent introduction to mRNA vaccines:
RNA vaccines: an introduction
CDC article on the different types of Covid-19 vaccines:
Understanding How COVID-19 Vaccines Work
Recent paper from La Jolla Institute for Immunology on SarsCoV2 immune duration:
Immunological memory to SARS-CoV-2 assessed for greater than six months after infection
Immune response to adenovirus vector:
Adeno-associated viral vector-mediated immune responses: Understanding barriers to gene delivery
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/
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