Dresden wrote:coldfish wrote:Posted this on the CA board but appropriate here:
Immunity from Pfizer's Covid-19 vaccine wanes, studies show
The immune protection offered by two doses of Pfizer's Covid-19 vaccine drops off after two months or so, although protection against severe disease, hospitalization and death remains strong, according to two real-world studies published Wednesday.
The studies -- from Israel and Qatar and published in the New England Journal of Medicine -- support arguments that even fully vaccinated people need to maintain precautions against infection.
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The study also indicated that immunity for people who get vaccinated after natural Covid-19 infection lasts longer. It's especially strong for people who recovered from infection and then got vaccinated, the study found.
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A second study from Qatar looked at actual infections among the highly vaccinated population of that small Gulf nation. People there mostly got Pfizer/BioNTech's vaccine.
The study found protection induced by the Pfizer vaccine "builds rapidly after the first dose, peaks in the first month after the second dose, and then gradually wanes in subsequent months," the research team wrote. "The waning appears to accelerate after the fourth month, to reach a low level of approximately 20% in subsequent months," they added.
Nonetheless, protection against hospitalization and death stayed at above 90%, researchers said.
https://www.cnn.com/2021/10/07/health/us-coronavirus-thursday/index.htmlIts funny but there were people online predicting how this was going to work a year and a half ago. The fact that experts and governments seems surprised is concerning.
A lot of the words above are true but misleading. The reality is that the only quick measure of immunity is antibodies and antibody levels fall rapidly. T Cells and B Cells are really hard to measure but they likely last a long time, if not a lifetime. The result is that you can get an infection again (just like every other coronavirus) but the severity is mitigated by the adaptive immune response.
Again, this gets back to the reality that everyone is going to get covid. By most analysis, more than half of americans have already had covid once. Keeping up on vaccination and boosters will make those cases less severe and eventually natural immunity will build to the point where its just a cold . . . just like the other coronaviruses (we think).
To be fair, there are people on line predicting just about anything, so that fact that a percentage of those predictions come true doesn't really say much.
As someone brought up earlier, the decision was made to rush the dosing in order to get people the full vaccine asap, instead of spacing them out by a few months, which would have produced better long term results. THus the need for a booster.
I suppose there is no way to ever know how many people actually have had Covid, since the antibodies produced when you get a vaccine are the same as when you had Covid. I'm not sure that everyone will eventually get Covid either. If enough people get vaccinated, there's no reason to think it can't be very limited in it's scope, as is measles for instance.
https://www.nature.com/articles/s41591-020-1083-1To detect reinfections, we measured increases in antibodies to the carboxyl (C)-terminal region of the nucleocapsid protein (NCt)—an immunodominant region of the structural coronavirus capsid protein4—for each seasonal coronavirus. The choice of the antigen, the serological test, the threshold for infection and the specificity and sensitivity of the tests are supplied in the Methods, Extended Data Figs. 1–4 and Supplementary Tables 1–3. A total of 101 events, ranging from 3 to 17 per individual, were classified as coronavirus infections (Table 1 and Fig. 1a). The time to reinfection was calculated only during continuous follow-up periods (connected dots in Fig. 1a and Supplementary Fig 1). The reinfection times ranged between 6 and 105 months (Fig. 1b). There was no statistically significant difference between the infection interval lengths of the individual viruses (Kruskal–Wallis test, P = 0.256), even though the number of HCoV-HKU1 infections was low and likely underestimated, most probably because of the low sensitivity of the HKU1-NCt-ELISA (Extended Data Fig. 2).
In a few cases, reinfections occurred as early as 6 months (twice with HCoV-229E and once with HCoV-OC43) and 9 months (once with HCoV-NL63), but reinfections were frequently observed at 12 months (Fig. 1b). For reinfections occurring as early as 6 months, we observed no intermediate reduction in antibodies between infections (Fig. 1b, white circles), but reinfection intervals of more than 6 months did show intermediate reductions between infections (visible as peaks in Fig. 1a and Supplementary Fig. 1). The ability to detect short-term reinfections in this study was limited by the sampling interval, which was, at minimum, 3 months. However, no signs of reinfection were observed at the first subsequent follow-up visit after a 3-month interval (Fig. 1b), as only decreases in antibody levels (optical density (OD) fold changes <1.0) were found (Fig. 1c). We, therefore, concluded that, in our data, the earliest time point for reinfection by seasonal coronaviruses was 6 months.
TLDR: People get infected with coronaviruses over and over, with the shortest period being 6 months.
The people who posted that this is going to be how it works out showed clinical studies exactly predicting the above behavior like the one above. To step back, some viruses create antibodies which are sterilizing immunity in the long term like chicken pox or measles. Other viruses, like coronaviruses are "get it and forget it" immunity where you are susceptible to another infection after months.
This was known before covid19 but just not publicized. It is extremely unlikely that the covid19 vaccine acts like a measles vaccine.
