key: cord-1047884-meco8rrb
authors: Zaqout, Ahmed; Daghfal, Joanne; Alaqad, Israa; Hussein, Saleh A.N.; Aldushain, Abdullah; Almaslamani, Muna A.; Abukhattab, Mohammed; Omrani, Ali S.
title: The initial impact of a national BNT162b2 mRNA COVID-19 vaccine rollout
date: 2021-05-13
journal: Int J Infect Dis
DOI: 10.1016/j.ijid.2021.05.021
sha: 483fdfb3a173c30e7be1d7e32281fe0f8623582d
doc_id: 1047884
cord_uid: meco8rrb

Objective We herein report the initial impact of a national BNT162b2 rollout on SARS-CoV-2 infections in Qatar. Methods We included all individuals who by 16 March 2021 had completed ≥14 days of follow up after the receipt of BNT162b2. We calculated incidence rates (IR) and their 95% confidence intervals (CI), during days 1–7, 8–14, 15–21, 22–28, and >28 days post-vaccination. Poisson regression was used to calculate incidence rate ratios (IRR) relative to the first 7-day post-vaccination period. Results We included 199,219 individuals with 6,521,124 person-days of follow up. SARS-CoV-2 infection was confirmed in 1,877 (0.9%), of which 489 (26.1%) were asymptomatic and 123 (6.6%) required oxygen support. The median time from first vaccination to SARS-CoV-2 confirmation was 11.9 days (IQR 7.7–18.2). Compared with the first 7-day post-vaccination period, SARS-CoV-2 infections were lower by 65.8–84.7% during days 15–21, days 22–28, and >28 days (P < 0.001 for each). For severe COVID-19, the incidence rates were 75.7–93.3% lower (P < 0.001 for each) during the corresponding time periods. Conclusion Our results are consistent with an early protective effect of BNT162b2 against all degrees of SARS-CoV-2 severity.

A two-dose regimen of BNT162b2, the was shown to reduce the risk of SARS-CoV-2 by around 95% in a randomized clinical trial, and in a mass national vaccination program. (Dagan et al., 2021; Polack et al., 2020) On 23

December 2020, Qatar started a national BNT162b2 rollout programme, in addition to existing COVID-19 public health control measures. The rollout initially prioritised healthcare workers, individuals aged ≥50 years, and those with chronic or immune suppressive medical conditions. We herein report the initial impact of BNT162b2 on SARS-CoV-2 infections in Qatar.

SARS-CoV-2 infections were confirmed using real-time PCR on upper or lower respiratory samples. BNT162b2 was supplied in multidose 0.45 mL vials, and was stored, prepared and administered according to the manufacturer's instructions. (Pfizer-BioNTech, 2021 We calculated SARS-CoV-2 infection incidence rates (IR), and their 95% confidence intervals (CI), per 100,000 person-days during five time-period: days <7 days, 8-14 days, 15-21 days, 22-28 days, and >28 days from receipt of the first BNT162b2 dose. Individuals stopped contributing person-days once SARS-CoV-2 infection was confirmed or at the study end date, whichever came first. We used Poisson regression to calculate incidence rate ratios (IRR) and their 95% CI for the latter four time-periods relative to IR during the first seven J o u r n a l P r e -p r o o f days from the first BNT162b2 dose. Statistical analyses were performed using Stata Statistical Software, Release 16.1 (StataCorp., College Station, Texas).

The included 199,219 individuals contributed 6,521,124 person-days of follow up. SARS-CoV-2 infection was confirmed in 1,877 (0.9%). The median time from first vaccination to SARS-CoV-2 confirmation was 11.9 days (IQR 7.7-18.2). A total of 242 (12.9%) individuals had confirmed COVID-19 after a second BNT162b2 dose, of which only 28 (1.5%) had confirmed COVID-19 more than 14 days after the second dose.

Compared with those without SARS-CoV-2 infection, infected individuals were significantly older, and more likely to have co-existing medical conditions (Table) . Cough (1,018, 54.2%) and fever (745, 39.7%) were the most frequent presenting symptoms, while infections were asymptomatic in 489 (26.1%). High-flow nasal oxygen or non-invasive ventilation was required for 28 (1.5%) individuals, invasive mechanical ventilation for 11 (0.6%), and oxygen via face mask or nasal cannula for 84 (4.5%). (Figure) .

Our findings are consistent with those shown previously in a community setting and in healthcare workers, but our report is the first to include an entire national cohort of BNT162b2 recipients. (Dagan et al., 2021; Hall et al., 2021) We also demonstrated a significant reduction in risk of severe COVID-19. This is particularly important, given its potential to reduce COVID-19-associated morbidity and mortality, and decrease its impact on healthcare resource utilization. (Hodgson et al., 2021) We found relatively high SARS-CoV-2 IR during the first two weeks following receipt of the There has been concern that VOC may reduce the effectiveness of some COVID-19 vaccines.(Abdool Karim and de Oliveira, 2021) However, BNT162b2 elicits high neutralising antibodies titres against B.1.1.7 and B.1.351 lineages. (Liu et al., 2021) Moreover, recently announced results from an ongoing phase 3 BNT162b2 randomised trial suggest it is highly effective against the B.1.351 lineage. (Pfizer and BioNTech, 2021) Deaths in our study mostly occurred in older individuals with multiple co-morbidities.

Vaccine effectiveness is generally lower in such groups. (Dagan et al., 2021) Notably, infected household contacts were identified in three out of the five fatal COVID-19 cases, reinforcing the importance of wide vaccine rollout to maximise protection of the most vulnerable. (Hodgson et al., 2021) The limitations of this study include its observational nature and the lack of a non-vaccinated control group. We used the first 7-day post-vaccination period, during which no vaccine effectiveness is expected, as a reference to assess the vaccine's protective benefits in later time-periods. Overall, our results are consistent with an early protective effect of BNT162b2 against all degrees of SARS-CoV-2 severity. It is anticipated that, in addition to ongoing nonpharmacological interventions, broader vaccine coverage will contribute to the national and global pandemic control efforts.

The study was approved by Hamad Medical Corporation's Institutional Review Board with a waiver of informed consent (MRC-01-21-207).

The authors declare no conflict of interests in relation to this manuscript.

The publication of this report was funded by Qatar National Library. No other funding was required.

The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper. 

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994 (21.6%)

Data are presented as number (%) or median (interquartile range). P values were derived from Pearson's chi-squared or Wilcoxon rank-sum test, as appropriate

We would like to thank Hussam Alsoub and Faraj S. Howady for their support during the preparation of this report.J o u r n a l P r e -p r o o f