Table 4 Sensitivity analyses for effectiveness of the mRNA-1273 vaccine against B.1.1.7 and B.1.351 infections and against severe, critical or fatal COVID-19 disease, after (1) matching by sex, age, nationality, reason for PCR testing and PCR test date, (2) adjusting for calendar week in logistic regression analysis and (3) adjusting for sex, age, nationality, reason for PCR testing and calendar week in logistic regression analysis

From: mRNA-1273 COVID-19 vaccine effectiveness against the B.1.1.7 and B.1.351 variants and severe COVID-19 disease in Qatar

 

≥14 Days after first dose and no second dose

≥14 Days after second dose

 

Cases, n (PCR-positive)

Controls, n (PCR-negative)

Effectiveness, % (95% CI)a

Cases, n (PCR-positive)

Controls, n (PCR-negative)

Effectiveness, % (95% CI)a

 

Vaccinated

Unvaccinated

Vaccinated

Unvaccinated

 

Vaccinated

Unvaccinated

Vaccinated

Unvaccinated

 

(1) Matching by sex, age, nationality, reason for PCR testing and PCR test date

Effectiveness against infection

Any infection with the B.1.1.7 variantb

14

12,828

97

12,745

85.7 (74.7–92.4)

0

11,689

6

11,683

100.0 (36.0–100.0)

Any infection with the B.1.351 variantc

158

29,153

404

28,907

61.2 (53.2–67.9)

2

27,789

39

27,752

94.9 (80.2–99.4)

Effectiveness against disease

Any severe, critical or fatal disease with any SARS-CoV-2 infectiond

6

1,799

30

1,775

80.3 (51.7–93.3)

0

1,580

0

1,580

Omittede

(2) Adjusting for calendar week in regression analysis

Effectiveness against infection

Any infection with the B.1.1.7 variantb

44

23,860

365

23,539

88.2 (83.8–91.4)

0

21,305

47

21,258

100.0 (Omittedf)

Any infection with the B.1.351 variantc

419

47,872

1,067

47,224

67.8 (63.8–71.3)

6

44,731

165

44,572

95.8 (90.6–98.2)

Effectiveness against disease

Any severe, critical or fatal disease with any SARS-CoV-2 infectiond

23

4,067

122

3,968

83.5 (74.0–89.6)

1

3,393

23

3,371

89.0 (15.2–98.6)

(3) Adjusting for sex, age, nationalityg, reason for PCR testing and calendar week in regression analysis

Effectiveness against infection

Any infection with the B.1.1.7 variantb

44

23,860

365

23,539

88.2 (83.8–91.4)

0

21,305

47

21,258

100.0 (Omittedf)

Any infection with the B.1.351 variantc

419

47,872

1,067

47,224

68.2 (64.3–71.7)

6

44,731

165

44,572

96.0 (90.9–98.2)

Effectiveness against disease

Any severe, critical or fatal disease with any SARS-CoV-2 infectiond

23

4,067

122

3,968

83.7 (74.1–89.7)

1

3,393

23

3,371

89.5 (18.8–98.7)

  1. aVaccine effectiveness was estimated using the test-negative, case-control study design17,18.
  2. bAny B.1.1.7 PCR-confirmed infection. A B.1.1.7 infection is proxied as an S-gene target failure case using the TaqPath COVID-19 Combo Kit platform (Thermo Fisher Scientific19), applying the criterion of PCR cycle threshold value ≤30 for both the N and ORF1ab genes but a negative outcome for the S-gene20,21,22.
  3. cAny B.1.351 PCR-confirmed infection. With essentially only B.1.351 and B.1.1.7 cases identified in the viral genome sequencing and the multiplex RT–qPCR variant screening between 8 March and 10 May 2021 (ref. 7), a B.1.351 infection is proxied as the complement of the B.1.1.7 criterion—that is, any infection with a Ct value ≤30 for the N, ORF1ab and S genes between the above dates.
  4. dAny PCR-confirmed infection that led to severe, critical or fatal COVID-19 disease. With the predominance of both B.1.1.7 and B.1.351 variants during the study period, this effectiveness is a combined measure against both of these variants. Severe disease, critical disease and COVID-19 death were defined based on the World Health Organization criteria for classifying SARS-CoV-2 infection severity23 and COVID-19-related death24.
  5. eThere were no vaccinated persons among cases and controls, and thus estimates could not be obtained.
  6. fThere were no events among individuals vaccinated.
  7. gNationality was included in the regression analysis as a categorical variable comprising the most populous nationalities in Qatar: Bangladeshi, Filipino, Egyptian, Indian, Nepalese, Pakistani, Qatari, Sudanese, Sri Lankan and other nationalities.
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