Assessing COVID-19 Vaccine Uptake and Effectiveness Through the North West London Vaccination Program: Retrospective Cohort Study (Preprint)

Abstract

BACKGROUND Real world data supporting the effectiveness of the COVID-19 vaccination strategy in the UK population is needed to guide health policy. This real-word data-driven evidence study of the UK COVID-19 Vaccination Programme in the Northwest London (NWL) population used a unique dataset established as part of the Gold Command Covid-19 response in NWL (iCARE https://imperialbrc.nihr.ac.uk/facilities/icare/), which included the pre-established Whole System Integrated Care (WSIC) data collated for the purposes of population health in the sector. OBJECTIVE To assess the early vaccine administration coverage and vaccine effectiveness and outcome data across an integrated care system of eight CCGs leveraging a unique population-level care dataset METHODS Design - Retrospective cohort study. Setting - Individuals eligible for COVID 19 vaccination in North West London based on linked primary and secondary care data. Participants - 2,183,939 individuals eligible for COVID 19 vaccination RESULTS During the NWL vaccine programme study time period 5.88% of individuals declined and did not receive a vaccination. Black or black British individuals had the highest rate of declining a vaccine at 16.14% (4,337). There was a strong negative association between deprivation and rate of declining vaccination (r=-0.94, p<0.01) with 13.5% of individuals declining vaccination in the most deprived postcodes compared to 0.98% in the least deprived postcodes. In the first six days after vaccination 344 of 389587 individuals tested positive for COVID-19 (0.09%). The rate increased to 0.13% (525/389,243) between days 7 and 13, before then gradually falling week on week. At 28 days post vaccination there was a 74% (HR 0.26 (0.19-0.35)) and 78% (HR 0.22 (0.18-0.27)) reduction in risk of testing positive for COVID -19 for individuals that received the Oxford/Astrazeneca and Pfizer/BioNTech vaccines respectively, when compared with unvaccinated individuals. After vaccination very low rates of hospital admission were seen in individuals testing positive for COVID-19 (0.01% of all patients vaccinated). CONCLUSIONS This study provides further evidence that a single dose of either the Pfizer/BioNTech vaccine or the Oxford/Astrazeneca vaccine is effective at reducing the risk of testing positive for COVID-19 up to 60 days across all adult age groups, ethnic groups, and risk categories in an urban UK population. There was no difference in effectiveness up to 28 days between the Oxford/Astrazeneca and Pfizer/BioNtech vaccines. In those declining vaccination higher rates were seen in those living in the most deprived areas and in Black and Black British groups. There was no definitive evidence to suggest COVID-19 was transmitted as a result of vaccination hubs during vaccine the administration roll-out in NWL, and the risk of contracting COVID-19 and/or becoming hospitalised after vaccination has been demonstrated to be very low in the vaccinated population.

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“…De estos pacientes, ocho (n=8) (53,33 %) ya se habían colocado la 1ra dosis de la vacuna Sputnik V. El tiempo promedio entre la aplicación de la vacuna y la aparición de los síntomas fue de veintitrés (23) días. No se incluyó a la primera paciente porque los lapsos entre la vacunación y el inicio de los síntomas fue de apenas 6 días, tiempo en el cual se están empezando a elevar los niveles séricos de los anticuerpos neutralizantes (20).…”

“…Desde el punto de vista de los exámenes de laboratorio, ambos grupos presentaron mayores elevaciones de la cuenta de glóbulos blancos, linfopenia, e incremento de los marcadores de inflamación e incluso de la relación neutrófilo/ linfocitos (Cuadro 10). El análisis inter grupo puso en evidencia que los incrementos de los parámetros hematológicos y reactantes de fase rápida fueron mayores en el grupo no vacunados, sugiriendo la presencia de un efecto protector de la vacuna (23).…”