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    Home > Active Ingredient News > Infection > JAMA: Vaccination and previous infections can reduce the risk of positive SARS-CoV-2 PCR test

    JAMA: Vaccination and previous infections can reduce the risk of positive SARS-CoV-2 PCR test

    • Last Update: 2021-06-16
    • Source: Internet
    • Author: User
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    The SARS-CoV-2 pandemic has severely affected international travel
    .
    With an effective
    COVID-19 vaccine, Qatar implemented a pilot program from February 18 to April 26, 2021 to relax travel restrictions and exempt residents who received a second dose of the vaccine at least 14 days before arrival Isolation requirements
    .
    The plan still requires polymerase chain reaction (PCR) testing for every passenger arriving at Hamad International Airport in Qatar

    .
    Roberto Bertollini and others investigated the incidence of positive PCR test results for arriving passengers

    .

    COVID-19

    The study analyzed all PCR test data of passengers arriving on international flights during the entire project period (February 18 to April 26, 2021), regardless of their departure country and vaccination status
    .
    Polymerase chain reaction test results, vaccination records and related demographic information are retrieved from the integrated Qatar digital health information platform, which has a SARS-CoV-2 database, which includes all polymerase chains in Qatar since the beginning of the pandemic Response testing and vaccination records

    .

    The study assessed whether vaccination (using BNT162b2 [Pfizer-Biotech] or mRNA-1273 [Moderna] vaccine) and previous infections are associated with a low risk of PCR positive testing
    .

    infection

    The study compared the PCR positive rates of vaccinated/previously infected people with those without vaccination/previous infection records.
    The two groups were matched one by one by age, gender, and nationality (in 40 ethnic groups), and the
    date of testing was controlled to control exposure The difference between risk and SARS-CoV-2 variant exposure
    .
    Full vaccination is defined as a second dose of vaccine at least 14 days before the PCR test at the airport
    .

    Test date to control the difference between exposure risk and SARS-CoV-2 mutation exposure
    .
    The definition of full vaccination is the second dose of vaccination at least 14 days before the PCR test at the airport.
    The definition of full vaccination is the second dose of vaccination at least 14 days before the PCR test at the airport.

    Reinfection was defined as the first PCR-positive swab at least 90 days after the previous infection
    .
    PCR-positive swabs less than 90 days before the airport PCR test and those who received only one dose of vaccination before the airport PCR test or those less than 14 days after the second dose of vaccination were excluded

    .

    Relative risk, related 95% CI and χ2 test were used to investigate its correlation with PCR positivity
    .
    Bilateral P≤0.
    05 indicates statistically significant relevant evidence

    .
    Use STATA/SE version 16.
    1 for analysis

    .
    Sequencing the virus genome of randomly collected PCR-positive inbound passenger specimens was used to determine the mutation

    .

    Research options for test subjects when they arrive at Qatar Airport from February 18 to April 26, 2021

    Research options for test subjects when they arrive at Qatar Airport from February 18 to April 26, 2021

    Upon arrival at the airport in Qatar, a total of 261,849 people (75.
    1% of men) were tested for SARS-CoV-2 PCR

    .
    The median age is 33 years (interquartile range 27-41 years)

    .
    31,190 fully vaccinated individuals (group 1; BNT162b2 was 99.
    7%, mRNA-1273 was 0.
    3%), 215,901 were individuals with no vaccination/previous infection records (group 2), 10092 could be matched, and the PCR positive rates were respectively They were 0.
    82% (95% CI, 0.
    66% ~ 1.
    01%) and 3.
    74% (95% CI, 3.
    37% ~ 4.
    12%)

    .
    9180 people have no vaccination records, but there are infection records at least 90 days before the airport test (group 3), 7694 people can be matched with group 2, and PCR positives are 1.
    01% (95% confidence interval, 0.
    80%--1.
    26%) ) And 3.
    81% (95% confidence interval, 3.
    39% -4.
    26%)

    .

    Correlation between vaccination/previous infection among Qatari residents returning by international flight and PCR positive on arrival at the airport

    Correlation between vaccination/previous infection among Qatari residents returning by international flight and PCR positive on arrival at the airport

     

    Compared with the record group that was not vaccinated or previously infected, the relative risk of vaccinated individuals for PCR positive was 0.
    22 (95% CI, 0.
    17-0.
    28), and the relative risk of PCR positive for individuals with a history of infection was 0.
    26 (95% CI, 0.
    21-0.
    34)

    .
    Sequencing of 72 PCR-positive specimens from inbound passengers revealed that B.
    1.
    351 (beta; n = 32; 44.
    4%), B.
    1.
    1.
    7 (α; n = 20; 27.
    8%), B.
    1.
    617 (delta; n = 8; 11.
    1%) and "wild type" strains (n ​​= 12; 16.
    7%)

    .

    Among Qatari residents returning from international flights, vaccination and previous infections are associated with a reduced risk of a positive SARS-CoV-2 PCR test
    .
    However, vaccine
    immunity and natural immunity are not perfect, and there are records of breakthrough infections
    .
    This highlights the need to maintain PCR testing for arriving travelers

    .
    Limitations include the use of records of previous positive PCR results to determine the history of previous infections, thereby missing people who had previously had mild or asymptomatic infections but were never tested

    .
    The research results may not be applicable to other airports, regions or domestic travel

    .

    Vaccinations and past infection SARS-CoV 2-PCR positive detection to reduce the risk associated with vaccination or past infection with SARS-CoV-2 PCR test positive for risk reduction related to immunity

    Original source

    Bertollini R, Chemaitelly H, Yassine HM, Al-Thani MH, Al-Khal A, Abu-Raddad LJ.
    Associations of Vaccination and of Prior Infection With Positive PCR Test Results for SARS-CoV-2 in Airline Passengers Arriving in Qatar.
     
    JAMA .
     Published online June 09, 2021.
    doi:10.
    1001/jama.
    2021.
    9970

    Bertollini R, Chemaitelly H, Yassine HM, Al-Thani MH, Al-Khal A, Abu-Raddad LJ.
    Associations of Vaccination and of Prior Infection With Positive PCR Test Results for SARS-CoV-2 in Airline Passengers Arriving in Qatar.
     
    JAMA .
     Published online June 09, 2021.
    doi:10.
    1001/jama.
    2021.
    9970
    Bertollini R, Chemaitelly H, Yassine HM, Al-Thani MH, Al-Khal A, Abu-Raddad LJ.
    Associations of Vaccination and of Prior Infection With Positive PCR Test Results for SARS-CoV-2 in Airline Passengers Arriving in Qatar.
     
    JAMA .
     Published online June 09, 2021.
    doi:10.
    1001/jama.
    2021.
    9970
    JAMA .
    JAMA

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