2021-09-15

T cells can reveal a covid infection even if antibodies waned

2021.8.4, 9.15: health/immunity/covid-19/

T cells can reveal a covid infection even if antibodies waned

9.15: summary:

. if you had a mild case of covid,

or it has been a while since you've been infected,

your antibody levels may be too low to measure,

but your T cells can still be measured

to determine if you've been exposed to covid virus.

. the CDC says you should get the vaccine

even if you have been infected,

so what's the use in knowing your status?

. you may be less likely to get sick again

if the vaccine doesn't cover some variants,

but the infection does cover the variants.

. you may want reassurance after vaccination

that even if the vaccine doesn't work on your variant,

you might still be protected by your infection.

. if you believe that, the CDC reminds you,

there are significant risks to getting infected;

not just death but also strange chronic illness;

so it's safer to get vaccinated than infected.

. even for children who are prone to having

bad reactions to the vaccine,

there are even more reactions to the virus.

. without any early treatment options available

(whether by politics or science)

there will be many more deaths from virus

than there will be deaths from vaccine.

21.8.4: news, web:

T-Detect COVID testing:

https://www.t-detect.com/covid-19/for-patients/

suggested price on Aug 4 for a Labcorp blood draw:

T-Detect COVID $150

PWNHealth test authorization $9

Total: $159


The T-Detect COVID price does not represent 

the usual and customary charge for the T-Detect COVID, 

and is subject to change. 


If you choose mobile phlebotomy through ExamOne, 

Adaptive will ship you a test kit

and ExamOne will schedule blood draw services 

via mobile phlebotomy (an in-home blood draw).


If you select a blood draw at a 

Labcorp patient service center, 

PWNHealth will place an order with Labcorp. 

You can schedule an appointment or walk in to

any of Labcorp’s patient service centers for a blood draw.


T cells are the first responders of the

adaptive immune system.

While antibodies naturally wane 

and are detectable in the shorter term, 

T cell responses can persist in the blood

up to several months after symptoms appear.


In 2 studies, the T-Detect COVID test

outperformed antibody tests.

High specificity: 

T cells can detect 70% of the parts of the virus, 

while antibodies can only detect 30%.

references:

Nat Immunol. 2021 May

https://www.ncbi.nlm.nih.gov/pmc/articles/pmid/33674800/

Robust SARS-CoV-2-specific T cell immunity

is maintained at 6 months following primary infection.

Jianmin Zuo, et al.


Vaccine. 2016 Apr

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7115611/

Memory T cell responses targeting the SARS coronavirus

persist up to 11 years post-infection.

Oi-Wing Ng, et al.


no peer review: 08 Jan 2021

https://www.medrxiv.org/content/10.1101/2021.01.06.21249345v1

Clinical Validation of a Novel T-cell Receptor

Sequencing Assay for Identification of

Recent or Prior SARS-CoV-2 Infection.

Sudeb C. Dalai, et al.

Here we describe clinical performance of

T- Detect™ COVID, 

the first reported assay to determine 

recent or prior SARS-CoV-2 infection

based on T-cell receptor (TCR) sequencing

and immune repertoire profiling 

from whole blood samples.

Competing Interest Statement:

SCD declares employment and equity ownership with

Adaptive Biotechnologies 

and employment with Stanford

University School of Medicine. 

TM and LB declare leadership, employment, 

and equity ownership with

Adaptive Biotechnologies. 

All other authors declare employment and 

equity ownership with

Adaptive Biotechnologies.


This test has not been FDA approved 

but has been authorized for emergency use

by FDA under an EUA.

The T-Detect COVID is currently not covered

by health insurance, but is HSA eligible.

T-Detect™ COVID is not indicated for use in

patients under age 18.


patient FAQ:

https://www.t-detect.com/covid-19/for-patients/


If I have a positive T-Detect COVID test, 

do I need to get a vaccine?

As of January 25, 2021, the CDC recommends

vaccination for most people, 

even if they have had a natural infection

with SARS-CoV-2.


CDC Jan. 25, 2020:

https://www.cdc.gov/coronavirus/2019-ncov/vaccines/faq.html

Yes, you should be vaccinated 

regardless of whether you already had COVID-19. 

That’s because experts do not yet know 

how long you are protected from getting sick again

after recovering from COVID-19. 


Even if you have already recovered from COVID-19, 

it is possible—although rare—

that you could be infected with the

virus that causes COVID-19 again. 

Studies have shown that vaccination provides

a strong boost in protection

in people who have recovered from COVID-19. 


Experts are still learning more about 

how long vaccines protect against COVID-19. 


more:

https://www.cdc.gov/coronavirus/2019-ncov/vaccines/vaccine-benefits.html

COVID-19 is still a threat to 

people who are unvaccinated. 

Some people who get COVID-19 can become

severely ill, which could result in

hospitalization, and some people have

ongoing health problems

[months] after getting infected. 

Even people who did not have symptoms 

when they were infected

can have these ongoing health problems.


more:

https://www.cdc.gov/vaccines/covid-19/clinical-considerations/covid-19-vaccines-us.html#CoV-19-vaccination

COVID-19 vaccination for People with 

prior or current SARS-CoV-2 infection:


People should be offered vaccination

regardless of their history of symptomatic or

asymptomatic SARS-CoV-2 infection; 

this includes people with 

prolonged post-COVID-19 symptoms. 


Data from clinical trials indicate that 

the currently authorized COVID-19 vaccines 

can be given safely to people with

evidence of a prior SARS-CoV-2 infection. 


Viral testing to assess for acute SARS-CoV-2 infection

or serologic testing to assess for prior infection

is not recommended for the purposes of

vaccine decision-making.


Vaccination of people with known

current SARS-CoV-2 infection

should be deferred until the person has

recovered from the acute illness

and they have met criteria to discontinue isolation. 

This recommendation applies to people who

experience SARS-CoV-2 infection

before [the vaccine dose series

has been started or completed.]


While there is no recommended 

minimum interval between infection and vaccination, 

current evidence suggests that 

the risk of SARS-CoV-2 reinfection

is low in the months after initial infection 

but may increase with time due to waning immunity.

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