Table 2.
RT-qPCR Ct values in the six pairwise comparisons including all infections.
| Study groupsa | N | Median | Difference in medians | IQR | Mean (95% CI) | SD | Difference in means (95% CI) | p value |
|---|---|---|---|---|---|---|---|---|
| Study 1 | ||||||||
| Primary infections in unvaccinated individuals | 4035 | 23.6 | 18.5–29.5 | 24.0 (23.8–24.2) | 6.5 | |||
| BNT162b2-vaccine breakthrough infections | 4035 | 24.7 | 1.1 | 19.2–30.9 | 25.0 (24.8–25.2) | 6.6 | 1.0 (0.7–1.2) | <0.001 |
| Study 2 | ||||||||
| Primary infections in unvaccinated individuals | 265 | 28.9 | 20.0–33.5 | 26.8 (25.9–27.6) | 7.1 | |||
| mRNA-1273-vaccine breakthrough infections | 265 | 32.6 | 3.7 | 27.3–34.7 | 30.3 (29.6–31.0) | 5.9 | 3.5 (2.5–4.5) | <0.001 |
| Study 3 | ||||||||
| BNT162b2-vaccine breakthrough infections | 227 | 29.0 | 20.0–33.5 | 27.1 (26.2–28.0) | 6.0 | |||
| mRNA-1273-vaccine breakthrough infections | 227 | 32.6 | 3.6 | 27.3–34.7 | 30.2 (29.4–31.0) | 7.0 | 3.1 (2.0–4.2) | <0.001 |
| Study 4 | ||||||||
| Primary infections in unvaccinated individuals | 1686 | 23.6 | 18.5–29.9 | 24.2 (23.8–24.5) | 6.6 | |||
| Reinfections in unvaccinated individuals | 1686 | 29.9 | 6.3 | 22.3–33.5 | 27.9 (27.6–28.3) | 6.5 | 3.8 (3.4–4.2) | <0.001 |
| Study 5 | ||||||||
| BNT162b2-vaccine breakthrough infections | 761 | 26.4 | 20.2–31.9 | 26.0 (25.5–26.4) | 6.5 | |||
| Reinfections in unvaccinated individuals | 761 | 29.5 | 3.1 | 22.0–33.4 | 27.7 (27.2–28.1) | 6.5 | 1.7 (1.1–2.3) | <0.001 |
| Study 6 | ||||||||
| mRNA-1273-vaccine breakthrough infections | 85 | 31.6 | 24.1–34.2 | 28.8 (27.3–30.3) | 6.8 | |||
| Reinfections in unvaccinated individuals | 85 | 33.0 | 1.4 | 29.4–34.4 | 30.8 (29.7–32.0) | 5.3 | 2.1 (0.3–3.8) | 0.022 |
RT-qPCR Ct values, for all confirmed infections, regardless of the reason for the RT-qPCR testing, in the six pairwise comparisons between primary infections in unvaccinated individuals, reinfections in unvaccinated individuals, BNT162b2-vaccine breakthrough infections, and mRNA-1273-vaccine breakthrough infections. Paired t-tests were used to compare the difference in means between study groups, with no adjustment for multiple comparisons. Two-sided p values are reported.
Ct cycle threshold, IQR interquartile range, RT-qPCR real-time reverse transcription polymerase chain reaction, SD standard deviation.
aStudy groups were matched in a 1:1 ratio by sex, 10-year age group, reason for RT-qPCR testing, and RT-qPCR test calendar week.