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

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

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

Relative risk, related 95% CI and χ2 test were used to investigate its correlation with PCR positivity
.

Bilateral P≤0.

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)

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.

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

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.

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 .
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