Annual Flu Vaccination - does it interfere with COVID infectivity?
It does seem to INcrease susceptibility to seasonal respiratory viruses.
One of the areas of my focus while doing my stint as a medical officer in NIH/NIAID, was to intensively look into the follow on safety of the H1N1 vaccines in babies and kids. We had tested the experimental vaccines with/without adjuvants, in this new cohort of flu vax recipients, because this influenza strain seem to uncharacteristically target the young. In the 2009 - 2011 time frame, a large fraction of the global population received at least one injection. What we were able to suss out from our multiple database healthcare partnerships was a disturbing trend of decreasing flu protection efficacy [as measured by flu episodes along with antibody generation to vaccination] with increasing doses of vaccines. Question: was this phenomenon limited to only the seasonal flu or was it due to a broader reduction in immune capacity?
A Hong Kong paper published in 2012 reported on that data from the kids.
We randomized 115 children to trivalent inactivated influenza vaccine (TIV) or placebo. Over the following 9 months, TIV recipients had an increased risk of virologically-confirmed non-influenza infections (relative risk: 4.40; 95% confidence interval: 1.31-14.8). Being protected against influenza, TIV recipients may lack temporary non-specific immunity that protected against other respiratory viruses.
The study pointed the finger at a diminished immune system generally, at least to common seasonal URI viruses.
MILITARY COHORT
A study of a military cohort examined the association of influenza vaccination status and positive respiratory infection rates during the 2017-2018 season. Data came from the Department of Defense Global Respiratory Pathogen Surveillance Program (DoDGRS), a DoD-wide program established by the Global Emerging Infections Surveillance and Response System (GEIS). Study Participants provided respiratory specimens to the DoDGRS for 2017-2018 influenza season. [The study was conducted by the Armed Forces Health Surveillance Branch Air Force Satellite at Wright-Patterson AFB, OH. Study population has a history of being heavily vaccinated.] :
When listing noninfluenza viruses specifically, the odds of both coronavirus and human metapneumovirus infections occuring in vaccinated individuals were significantly higher when compared to unvaccinated individuals (OR = 1.36 and 1.51, respectively). The flu vaccine that was administered to these troops showed varied benefit in actually preventing flu – it was very dependent on specific virus strain. Some showed significant benefit while others did not.
ELDERLY GLOBAL POPULATION
Early 2020, Korea and Italy reported outbreaks of COVID cases. At the time they were also pushing the seasonal flu vaccine. But South Korea saw a total of 83 people, most of whom are elderly, dying soon after being administered the vax. Of the total, 37 people are in their 70s, followed by 34 people aged 80 or older, eight under 60 and four in their 60s. It was enough of a concern for Singapore to halt the use of two influenza vaccines as a precaution.
By October 2020, there was enough evidence accumulated to review global trends, at least as related to the elderly cohort, which was most affected and was the largest cohort in the deaths.
To determine the association between COVID-19 deaths and influenza vaccination, available data sets from countries with more than 0.5 million inhabitants were analyzed (in total 39 countries). To accurately estimate the influence of IVR (Influenza Vaccination Rate) on COVID-19 deaths and mitigate effects of confounding variables, a sophisticated ranking of the importance of different variables was performed, including as predictor variables IVR and some potentially important geographical and socioeconomic variables as well as variables related to non-pharmaceutical intervention. The associations were measured by non-parametric Spearman rank correlation coefficients and random forest functions.
Results
The results showed a positive association between COVID-19 deaths and IVR of people ≥65 years-old. There is a significant increase in COVID-19 deaths from eastern to western regions in the world. - C Wehenkel 2020
July 2020 raw data:
MECHANISMS OF ACTION?
Now what could be the mechanism of action of this ‘viral interference’?
While influenza vaccination offers specific protection against targeted influenza strains, a natural influenza infection from wild type strains may actually reduce the risk of non-influenza respiratory viruses by providing temporary, non-specific broad immunity against those viruses. Vaccinated individuals may be at increased risk for other respiratory viruses because they do not receive the boost in non-specific immunity associated with natural infection.
Another hypothesis involves the phenomenon of ADE (Antibody Dependent Enhancement). In this case non-neutralizing antibodies (less specific, less potent) may bind to the infecting virus and ENHANCE its ability to fuse with cells, hence increase viral replication. Most vaccines for enveloped RNA viruses such as influenza and SARS-CoV-2 immunize with the surface spike protein involved in docking with the fusion peptide. Perhaps the nonspecific Abs generated by the modified spike antigen in the vaccine, lead to the enhancement.
Answers are still unknown. But these questions should be queried with each and every flu vax campaign.
What, exactly, are we really trying to accomplish?
REFERENCES
BJ Cowling et al. Increased Risk of Noninfluenza Respiratory Virus Infections Associated With Receipt of Inactivated Influenza Vaccine Clinical Infectious Diseases, 54, (12) 15 June 2012, pp 1778–1783 https://academic.oup.com/cid/article/54/12/1778/455098
GG Wolff. Influenza vaccination and respiratory virus interference among Department of Defense personnel during the 2017–2018 influenza season. Vaccine 38 (2) 10 January 2020, pp 350-354 https://www.sciencedirect.com/science/article/pii/S0264410X19313647?via%3Dihub
83 deaths reported among people who received flu vaccine: authorities http://www.koreaherald.com/view.php?ud=20201031000051
Singapore suspends using two flu vaccines after 48 patients die in South https://www.scmp.com/news/asia/southeast-asia/article/3107075/singapore-halts-flu-vaccines-after-48-patients-die-south
C Wehenkel. Positive association between COVID-19 deaths and influenza vaccination rates in elderly people worldwide. Peer J October 1, 2020 https://peerj.com/articles/10112/
AN Vzorov et al. Modification of the Spike Protein for Vaccines against Enveloped RNA Viruses. Molecular Biology, 2021, Vol. 55, No. 4, pp. 538–547. https://link.springer.com/content/pdf/10.1134/S0026893321030158.pdf
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