I posted this in a thread, but it seems worth a top post with recent info as there are many discussions on the vaxes, immunity and boosters.
"Acquired Immunity" occurs by vax or infection. A large portion of the world has acquired immunity and likely T-cell protection. We saw last Spring in Hong Kong what can happen without it even with "milder" Omicron , low vax rates in seniors there led to many bad outcomes.
Acquired immunity is one reason we don't see so many near death results as we did 2 years ago. (I knew plenty including my Hubby) Even if our vaxes are not fresh, and our last infection was some time ago, the data and reports below indicates we retain protection from the worst outcomes.
-Below is t-cell info for general, immune compromised, and MPN specific. MF is reported to be associated with some reduced t-cell response, and per one report, don't stop Rux if you're infected.
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Info has been accumulating that t-cells provide protection absent the more familiar immune response we read about. Problem is t-cells are hard and expensive to test.
T-cells provide long term memory and some work by killing infected cells. But t-cells start to work after you're infected, so they don't "prevent" infection in the way we've been trained to think of it, (this is a subject of some posts here) rather they kick start the response once infected.
The last words in the mouse study below are right on the point "...protect-against-covid-19-absence-antibody-response" But I read recently a good quote, for studies "mice lie and monkeys exaggerate". But the human clinical info here is compelling.
Some reports thru time:
2022- <<This breadth of recognition (via t-cells) can limit the impact of individual viral mutations and is likely to underpin protection against severe disease from viral variants, including Omicron... Current COVID-19 vaccines elicit robust T cell responses that likely contribute to remarkable protection against hospitalization or death ... T cell immunity plays a central role in the control of SARS-CoV-2 and its importance may have been relatively underestimated thus far.>>
nature.com/articles/s41590-...
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2022- <<This study suggests that cross-reactive SARS-CoV-2-specific T-cell responses could be particularly important in the protection against severe disease caused by variants of concern whereas neutralising antibody responses (the one most of us focus on) seem to reduce over time.>>
thelancet.com/journals/lanm...
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2021- <<Robust T-Cell Response to mRNA COVID-19 Vaccines—a More Durable Source of Protection>>
pennmedicine.org/news/news-...
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2020- <<T cells found in COVID-19 patients ‘bode well' for long-term immunity>>
science.org/content/article...
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And a good mouse study that tested with normal t cells and with t-cells removed to confirm the t-cells actually worked:
<<In studies of mice, immune cells called T cells protected animals against COVID-19 even in the absence of antibodies targeting the SARS-CoV-2 virus>>
nih.gov/news-events/nih-res...
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For MPN, some pattern of MF being lower response in this report but generally good t-cells:
2021- <<For the first time, we have demonstrated that patients with chronic MPN can mount functional memory T-cell responses following natural SARS-CoV-2 exposure...Patients with chronic MPN without detectable antibodies had a T-cell response that was broadly equivalent in many areas to that seen in those with detectable anti-SARS-CoV-2 antibodies.>>
Negatives were <<older patients, those with myelofibrosis (MF) and those who had sudden discontinuation of ... ruxolitinib had worse outcomes.>>
onlinelibrary.wiley.com/doi...
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For MPN patients an uncertain result in this report with possible reduction in t-cell response:
<<We found a lower magnitude of T-cell responses ... in MPNs compared to healthy controls, although this finding was partially confounded by the older age of MPN patients.>>
nature.com/articles/s41375-...
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For MF patients, the t-cell response was reduced but :
<<the memory T cell response reported here may prove to be particularly important with regards to ongoing immunity against SARS-CoV-2....A memory T cell response was observed in 80% (16) of patients, with a CD4+ T cell response in 75% and a CD8+ T cell response in 35% >> This was a small sample size.
news.cancerconnect.com/myel...
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A report on general immune compromised using a powerful suppressant (not Rux):
<<B-cell depletion following rituximab impairs serological responses, but T-cell responses are preserved in this group>>
ard.bmj.com/content/80/10/1322
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For another group of immune comp missing antibodies still allows for T-cell protection:
<<Even in the absence of SARS-CoV-2 antibodies, IBD patients showed significant T cell responses after first SARS-CoV-2 vaccination compared with healthy controls, which was not influenced by different immunosuppressive regimens.>>
Impact of COVID-19 infection in blood cancer patients
