20.11.30: web,aq.med/redcross/
health/immunity/covid-19/my covid-19 antibody test is negative:
summary:
. I got a covid-19 antibody test
from giving blood to the redcross;
and it came back negative,
but while that could mean I never got exposed,
it could also mean I had a mild case of covid-19
where my immune response made very few antibodies,
and within 8 months, I make undetectable levels.
my covid-19 antibody test:
https://www.redcrossblood.org/give.html/donation-history
Negative test result:
Indicates that you probably have
not been exposed to COVID-19
and therefore have not developed antibodies to the virus.
It also could indicate that
antibodies are present but at levels below
the test’s threshold for detection,
or that the test did not recognize those antibodies.
It is possible that you can still contract the virus, if exposed.
It takes one to three weeks after an infection
for antibodies to be present.
search:
I felt I got covid-19 in March;
is it possible I lost my antibodies by November? yes:
cdc: you can get covid-19 without making antibodies:
https://www.cdc.gov/coronavirus/2019-ncov/lab/resources/antibody-tests-guidelines.html
"Antibodies may not be present ... among those who
never develop detectable antibodies following infection."
mild cases make less antibodies:
https://www.click2houston.com/news/local/2020/11/28/covid-19-immunity-how-long-do-antibodies-last/
. non-peer reviewed, pre-print paper
from the Imperial College of London,
antibody levels were tracked in 365,000 people in England
from June 20
through September 28.
Researchers found that in June,
6% of the population had antibodies;
By September,
only 4.4% of the people tested had antibodies.
Another new study from the journal Nature Microbiology
found that over 95% of the patients developed an antibody response
after eight days from symptom onset,
but the amount of neutralizing antibody produced was
highest in patients with the most severe symptoms.
People who produced the highest levels of antibodies
continued to produce them for more than two months
after their initial infection.
But for those who initially produced fewer antibodies,
[because like me they had only mild symptoms]
their antibodies became undetectable within
a month and a half.
nature medicine letters 18 June 2020
https://www.nature.com/articles/s41591-020-0965-6?MvBriefArticleId=34327
Clinical and immunological assessment of
asymptomatic SARS-CoV-2 infections.
. median duration of viral shedding in the
asymptomatic group was 19 d (interquartile range (IQR), 15–26 d).
The asymptomatic group had a significantly
longer duration of viral shedding
than the symptomatic group (log-rank P = 0.028).
The virus-specific IgG levels in the asymptomatic group
(median S/CO, 3.4; IQR, 1.6–10.7) were significantly lower (P = 0.005)
relative to the symptomatic group (median S/CO, 20.5; IQR, 5.8–38.2) in the acute phase.
Of asymptomatic individuals,
93.3% (28/30) and 81.1% (30/37) had reduction in
IgG and neutralizing antibody levels, respectively,
during the early convalescent phase,
as compared to 96.8% (30/31) and 62.2% (23/37) of symptomatic patients.
Forty percent of asymptomatic individuals became seronegative
and 12.9% of the symptomatic group became negative for IgG
in the early convalescent phase.
In addition, asymptomatic individuals exhibited lower levels of
18 pro- and anti-inflammatory cytokines.
These data suggest that asymptomatic individuals
had a weaker immune response to SARS-CoV-2 infection.
The reduction in IgG and neutralizing antibody levels
in the early convalescent phase
might have implications for immunity strategy and serological surveys.
Dr. Kari Nadeau at Stanford University:
"T cells are very important in fighting viruses,"
"And so, one thing we're looking at,
as the antibodies wane, do the T-cell responses also wane?"
. some coronavirus vaccines have resulted in
a strong T-cell response.
....
what really amazed me from this research is that
while they ask the infected to isolate for
14 days,
the asymptomatic cases can be shedding and
spreading virus for up to
26 days (nearly twice as long) in one sample.
. the asymptomatic can be considered
virus non-responders;
I wonder if they will also be
vaccine non-responders?
. at least if they are still infectious after the vaccine,
the vaccine will reduce the severity of covid-19
in the vulnerable hyper-responders.
. I'm not generally vaccine-hesitant,
but last time I got a flu vaccine,
my arm continued to hurt for 6 months:
I spend much of my time lifting my arms to do typing on my laptop,
and the vaccinated shoulder muscle hurt whenever I
lifted my arm and asked that muscle to contract.
. I wondered if they got too close to the bone,
or if my immune system damaged my muscle.
. the only cases of vaccine shoulder injury I could find
were where the injection was too high and got in the joint;
then people complained they couldn't lift their arm after that.
. I read somewhere that the Japanese
(smaller people with less shoulder muscle?)
thought shoulder injections were a bad idea
and aim for the leg muscle instead.
20.12.4: news.health/immunity/covid-19/
asymptomatic infections are not viral vectors:
Dr.Mercola comments on this study:
Nature Communications 2020:
https://www.nature.com/articles/s41467-020-19802-w
Post-lockdown SARS-CoV-2 nucleic acid screening
in nearly ten million residents of Wuhan, China.
"not a single one of those who had
been in close contact with an asymptomatic individual
tested positive."
"When asymptomatic patients were tested for antibodies,
they discovered that 190 of the 300, or 63.3%,
had actually had a “hot” or productive infection
resulting in the production of antibodies.
Still, none of their contacts had been infected."
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