Tags

Type your tag names separated by a space and hit enter

Effectiveness of mRNA vaccines and waning of protection against SARS-CoV-2 infection and severe covid-19 during predominant circulation of the delta variant in Italy: retrospective cohort study.
BMJ. 2022 02 10; 376:e069052.BMJ

Abstract

OBJECTIVES

To estimate the effectiveness of mRNA vaccines against SARS-CoV-2 infection and severe covid-19 at different time after vaccination.

DESIGN

Retrospective cohort study.

SETTING

Italy, 27 December 2020 to 7 November 2021.

PARTICIPANTS

33 250 344 people aged ≥16 years who received a first dose of BNT162b2 (Pfizer-BioNTech) or mRNA-1273 (Moderna) vaccine and did not have a previous diagnosis of SARS-CoV-2 infection.

MAIN OUTCOME MEASURES

SARS-CoV-2 infection and severe covid-19 (admission to hospital or death). Data were divided by weekly time intervals after vaccination. Incidence rate ratios at different time intervals were estimated by multilevel negative binomial models with robust variance estimator. Sex, age group, brand of vaccine, priority risk category, and regional weekly incidence in the general population were included as covariates. Geographic region was included as a random effect. Adjusted vaccine effectiveness was calculated as (1-IRR)×100, where IRR=incidence rate ratio, with the time interval 0-14 days after the first dose of vaccine as the reference.

RESULTS

During the epidemic phase when the delta variant was the predominant strain of the SARS-CoV-2 virus, vaccine effectiveness against SARS-CoV-2 infection significantly decreased (P<0.001) from 82% (95% confidence interval 80% to 84%) at 3-4 weeks after the second dose of vaccine to 33% (27% to 39%) at 27-30 weeks after the second dose. In the same time intervals, vaccine effectiveness against severe covid-19 also decreased (P<0.001), although to a lesser extent, from 96% (95% to 97%) to 80% (76% to 83%). High risk people (vaccine effectiveness -6%, -28% to 12%), those aged ≥80 years (11%, -15% to 31%), and those aged 60-79 years (2%, -11% to 14%) did not seem to be protected against infection at 27-30 weeks after the second dose of vaccine.

CONCLUSIONS

The results support the vaccination campaigns targeting high risk people, those aged ≥60 years, and healthcare workers to receive a booster dose of vaccine six months after the primary vaccination cycle. The results also suggest that timing the booster dose earlier than six months after the primary vaccination cycle and extending the offer of the booster dose to the wider eligible population might be warranted.

Authors+Show Affiliations

Italian National Institute of Health (ISS), Rome, Italy massimo.fabiani@iss.it.Italian National Institute of Health (ISS), Rome, Italy.Italian National Institute of Health (ISS), Rome, Italy.Italian National Institute of Health (ISS), Rome, Italy.Italian National Institute of Health (ISS), Rome, Italy.Italian National Institute of Health (ISS), Rome, Italy.Italian National Institute of Health (ISS), Rome, Italy.Italian National Institute of Health (ISS), Rome, Italy.Italian National Institute of Health (ISS), Rome, Italy.Italian National Institute of Health (ISS), Rome, Italy.Italian Ministry of Health, Rome, Italy.Italian National Institute of Health (ISS), Rome, Italy.Italian National Institute of Health (ISS), Rome, Italy.Italian National Institute of Health (ISS), Rome, Italy.Italian National Institute of Health (ISS), Rome, Italy.Italian Ministry of Health, Rome, Italy.Italian Ministry of Health, Rome, Italy.Italian National Institute of Health (ISS), Rome, Italy.Italian National Institute of Health (ISS), Rome, Italy.Italian National Institute of Health (ISS), Rome, Italy.Italian National Institute of Health (ISS), Rome, Italy.Italian Ministry of Health, Rome, Italy.Italian National Institute of Health (ISS), Rome, Italy.Italian National Institute of Health (ISS), Rome, Italy.No affiliation info available

Pub Type(s)

Journal Article

Language

eng

PubMed ID

35144968

Citation

Fabiani, Massimo, et al. "Effectiveness of mRNA Vaccines and Waning of Protection Against SARS-CoV-2 Infection and Severe Covid-19 During Predominant Circulation of the Delta Variant in Italy: Retrospective Cohort Study." BMJ (Clinical Research Ed.), vol. 376, 2022, pp. e069052.
Fabiani M, Puopolo M, Morciano C, et al. Effectiveness of mRNA vaccines and waning of protection against SARS-CoV-2 infection and severe covid-19 during predominant circulation of the delta variant in Italy: retrospective cohort study. BMJ. 2022;376:e069052.
Fabiani, M., Puopolo, M., Morciano, C., Spuri, M., Spila Alegiani, S., Filia, A., D'Ancona, F., Del Manso, M., Riccardo, F., Tallon, M., Proietti, V., Sacco, C., Massari, M., Da Cas, R., Mateo-Urdiales, A., Siddu, A., Battilomo, S., Bella, A., Palamara, A. T., ... Pezzotti, P. (2022). Effectiveness of mRNA vaccines and waning of protection against SARS-CoV-2 infection and severe covid-19 during predominant circulation of the delta variant in Italy: retrospective cohort study. BMJ (Clinical Research Ed.), 376, e069052. https://doi.org/10.1136/bmj-2021-069052
Fabiani M, et al. Effectiveness of mRNA Vaccines and Waning of Protection Against SARS-CoV-2 Infection and Severe Covid-19 During Predominant Circulation of the Delta Variant in Italy: Retrospective Cohort Study. BMJ. 2022 02 10;376:e069052. PubMed PMID: 35144968.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Effectiveness of mRNA vaccines and waning of protection against SARS-CoV-2 infection and severe covid-19 during predominant circulation of the delta variant in Italy: retrospective cohort study. AU - Fabiani,Massimo, AU - Puopolo,Maria, AU - Morciano,Cristina, AU - Spuri,Matteo, AU - Spila Alegiani,Stefania, AU - Filia,Antonietta, AU - D'Ancona,Fortunato, AU - Del Manso,Martina, AU - Riccardo,Flavia, AU - Tallon,Marco, AU - Proietti,Valeria, AU - Sacco,Chiara, AU - Massari,Marco, AU - Da Cas,Roberto, AU - Mateo-Urdiales,Alberto, AU - Siddu,Andrea, AU - Battilomo,Serena, AU - Bella,Antonino, AU - Palamara,Anna Teresa, AU - Popoli,Patrizia, AU - Brusaferro,Silvio, AU - Rezza,Giovanni, AU - Menniti Ippolito,Francesca, AU - Pezzotti,Patrizio, AU - ,, Y1 - 2022/02/10/ PY - 2022/2/11/entrez PY - 2022/2/12/pubmed PY - 2022/2/22/medline SP - e069052 EP - e069052 JF - BMJ (Clinical research ed.) JO - BMJ VL - 376 N2 - OBJECTIVES: To estimate the effectiveness of mRNA vaccines against SARS-CoV-2 infection and severe covid-19 at different time after vaccination. DESIGN: Retrospective cohort study. SETTING: Italy, 27 December 2020 to 7 November 2021. PARTICIPANTS: 33 250 344 people aged ≥16 years who received a first dose of BNT162b2 (Pfizer-BioNTech) or mRNA-1273 (Moderna) vaccine and did not have a previous diagnosis of SARS-CoV-2 infection. MAIN OUTCOME MEASURES: SARS-CoV-2 infection and severe covid-19 (admission to hospital or death). Data were divided by weekly time intervals after vaccination. Incidence rate ratios at different time intervals were estimated by multilevel negative binomial models with robust variance estimator. Sex, age group, brand of vaccine, priority risk category, and regional weekly incidence in the general population were included as covariates. Geographic region was included as a random effect. Adjusted vaccine effectiveness was calculated as (1-IRR)×100, where IRR=incidence rate ratio, with the time interval 0-14 days after the first dose of vaccine as the reference. RESULTS: During the epidemic phase when the delta variant was the predominant strain of the SARS-CoV-2 virus, vaccine effectiveness against SARS-CoV-2 infection significantly decreased (P<0.001) from 82% (95% confidence interval 80% to 84%) at 3-4 weeks after the second dose of vaccine to 33% (27% to 39%) at 27-30 weeks after the second dose. In the same time intervals, vaccine effectiveness against severe covid-19 also decreased (P<0.001), although to a lesser extent, from 96% (95% to 97%) to 80% (76% to 83%). High risk people (vaccine effectiveness -6%, -28% to 12%), those aged ≥80 years (11%, -15% to 31%), and those aged 60-79 years (2%, -11% to 14%) did not seem to be protected against infection at 27-30 weeks after the second dose of vaccine. CONCLUSIONS: The results support the vaccination campaigns targeting high risk people, those aged ≥60 years, and healthcare workers to receive a booster dose of vaccine six months after the primary vaccination cycle. The results also suggest that timing the booster dose earlier than six months after the primary vaccination cycle and extending the offer of the booster dose to the wider eligible population might be warranted. SN - 1756-1833 UR - https://www.unboundmedicine.com/medline/citation/35144968/Effectiveness_of_mRNA_vaccines_and_waning_of_protection_against_SARS_CoV_2_infection_and_severe_covid_19_during_predominant_circulation_of_the_delta_variant_in_Italy:_retrospective_cohort_study_ DB - PRIME DP - Unbound Medicine ER -