Coronavirus (40) Nationwide COVID-19 immunization in the UK
Five months have passed since the UK started its vaccination rollout last December. You might wonder the concerns about the side-effects after vaccination and the efficacy of the vaccines against COVID-19 in the general population. Surveillance reports from the UK’s vaccination programme using Pfizer-BioNTech (BNT162b2, mRNA vaccine) and Oxford-AstraZeneca (ChAdOx1 nCoV-19, non-replicated adenovirus vectored vaccine) COVID-19 vaccines has been published recently.1 Although the vaccination campaign in the UK is still ongoing, the data from the report gives us some idea of the above issues.
Background of the surveillance report from the UK
The surveillance report from the UK analysed data collected from individuals using a COVID Symptom Study app, which was developed by a health science company ZOE and was launched at the end of March 2020. The research is led by ZOE co-founder, Professor Tim Spector at King’s College London. Data collected is shared with and analysed by King's College London and ZOE research teams.
The reports covered the period from the first day of the vaccine campaign, 8 December 2020, to 10 March 2021. The nationwide vaccination programme in the UK prioritized senior citizens and the most vulnerable groups.2 According to the COVID-19 vaccine monitoring statistics data provided by the NHS,3 by 14th March, at least one dose of vaccine had been given to the adults aged over 50, front-line health and social care workers (those who participated in the ZOE study had a median age of 46.1 years),4 staff working in care homes, clinically extremely vulnerable individuals, and the adults aged 16 to 65 years in an at-risk group.
The BNT162b2 (Pfizer) vaccination was first rolled out on 8 December 2020, while the ChAdOx1 nCoV-19 (Oxford/AstraZeneca) vaccination was first rolled out on 4 January 2021. Both vaccines are two-dose regimens. However, individuals will be given the second dose at 10-12 weeks after the first dose, rather than 21 days as per the guidance of the vaccine manufacturers. By the end of the analysis period, some people already had both doses of BNT162b2 (Pfizer) vaccines.
The COVID Symptom Study app allows self-reporting of systemic and local side effects for individuals who received one or both doses of the BNT162b2 (Pfizer) vaccine, or the first dose of the ChAdOx1 nCoV-19 (Oxford/AstraZeneca) vaccine. Side effects were monitored for the following 8 days after a vaccination. A subset of individuals also reported receiving a test for SARS-CoV-2 infection by either PCR or lateral flow test. The study also compared infection rates in a subset of vaccinated individuals (subsequently tested for SARS-CoV-2 with PCR or lateral flow tests) with infection rates in unvaccinated controls.1
The side effects of both vaccines
During the analysis period, the COVID Symptom Study app received 627,383 reports of individuals being vaccinated: 282,103 received at least one dose of BNT162b2 (Pfizer), while 345,280 individuals reported being vaccinated with one dose of ChAdOx1 nCoV-19 (Oxford/AstraZeneca).
From the self-report system, it seems that systemic (whole body) side-effects were higher in participants who received ChAdOx1 nCoV-19 (Oxford/AstraZeneca). Systemic side-effects were reported by 13.5% and 22.0% of individuals after the first dose and the second dose respectively of BNT162b2 (Pfizer), while 33.7% of individuals receiveing the first dose of ChAdOx1 nCoV-19 (Oxford/AstraZeneca) reported systemic side-effects. The most commonly reported systemic side-effects were fatigue and headache for both vaccines. They were most frequently reported within the first 24 hours after vaccination, and lasted for about 1 day.
The reported local side-effects were more frequent than the systemic side-effects. However, by contrast with the systemic side-effects, local side-effects were more frequent in participants who received BNT162b2 (Pfizer): 71.9% and 68.5% of individuals reported local side-effects after the first dose and the second dose of BNT162b2, respectively, while 58.7% of individuals reported local side-effects after the first dose of ChAdOx1 nCoV-19. The most frequent local side-effects are tenderness and local pain around the injection site, which occurred most often on the day after injection and lasted for about 1 day. The less frequent side-effects include allergic skin reactions such as skin burning, rashes, and red welts on the lips and face, which was reported in 1.7% of 627,383 users across both types of vaccine.
Both systemic side effects and local side effects of both vaccines were more common among individuals with previous SARS-CoV-2 infection than among those without known past infection. After the first dose of BNT162b2 (Pfizer), systemic side effects and local side effects were 2.9 times and 1.2 times as high among individuals with previous SARS-CoV-2 infection than among those without known past infection. Meanwhile, after ChAdOx1 nCoV-19 (Oxford/AstraZeneca) vaccination, systemic side-effects and local side-effects were 1.6 times and 1.4 times as high among individuals with previous SARS-CoV-2 infection than among those without known past infection. Similar findings had been reported before.5,6 It seems that the previous infection leads to a higher immune response, which is reflected by the systemic side-effects, in a subsequent infection.
In line with the above findings, among the individuals (28,207) who reported having two BNT162b2 (Pfizer) doses, a higher percentage of systemic side-effects were being reported in individuals after the second dose. There were 3325 (11.7%) reporting at least one systemic side effect after the first dose, compared with 6216 (22.0%) after the second dose.
Infection rates after the vaccination of both vaccines
The study analysed infection rates at 0–4, 5–11, 12–20, 21–44, and 45–59 days after vaccination. It was found that the infection risk was significantly reduced starting at 12 days after the first dose of BNT162b2 (Pfizer), reaching 69% at 21–44 days and 72% after 45–59 days. For ChAdOx1 nCoV-19 (Oxford/AstraZeneca), the risk of infection was significantly reduced starting at 12 days after the first dose, reaching 60% later on.
Moreover, the data showed that the vaccines were more effective in younger and slimmer people with no more than one illness. For both vaccines, the reduction of infection was more significant in individuals aged 55 years or younger than in individuals older than 55 years; it was also more significant in those without comorbidity than in those with one or more comorbidities, and in individuals with a BMI of less than 30 kg/m2 than in those with BMI of 30 kg/m2 or higher.
The surveillance report showed us that the systemic side-effects of both vaccines, BNT162b2 and ChAdOx1 nCoV-19, are not highly prevalent. And the findings that the efficacy of the two vaccines are more than 60% 12 days after the injection should give us confidence to have vaccination if we have not had one. This should also encourage the individuals to have the second dose in order to get a higher protection from the vaccine.
References
1. C. Menni, K. Klaser, A. May, et al. Vaccine side-effects and SARS-CoV-2 infection after vaccination in users of the COVID Symptom Study app in the UK: a prospective observational study. Lancet Infect Dis., 2021 Apr 27. S1473-3099(21)00224-3. doi: 10.1016/S1473-3099(21)00224-3.
2. COVID-19 vaccination first phase priority groups. NHS website. Updated 23 April 2021. https://www.gov.uk/government/publications/covid-19-vaccination-care-home-and-healthcare-settings-posters/covid-19-vaccination-first-phase-priority-groups
3. COVID-19 vaccination statistics. By NHS. https://www.england.nhs.uk/statistics/wp-content/uploads/sites/2/2021/03/COVID-19-weekly-announced-vaccinations-18-March-2021.pdf
4. V.J. Hall, S. Foulkes, A. Saei, et al. COVID-19 vaccine coverage in health-care workers in England and effectiveness of BNT162b2 mRNA vaccine against infection (SIREN): a prospective, multicentre, cohort study. Lancet. 2021; (published online April 23.)
5. F. Krammer, K. Srivastava, and V. Simon. Robust spike antibody responses and increased reactogenicity in seropositive individuals after a single dose of SARS-CoV-2 mRNA vaccine. medRxiv, 2021; published online Feb 1. doi: https://doi.org/10.1101/2021.01.29.21250653
6. J. Wise. COVID-19: people who have had infection might only need one dose of mRNA vaccine. BMJ, 2021 Feb 2;372:n308. doi: 10.1136/bmj.n308.
Five months have passed since the UK started its vaccination rollout last December. You might wonder the concerns about the side-effects after vaccination and the efficacy of the vaccines against COVID-19 in the general population. Surveillance reports from the UK’s vaccination programme using Pfizer-BioNTech (BNT162b2, mRNA vaccine) and Oxford-AstraZeneca (ChAdOx1 nCoV-19, non-replicated adenovirus vectored vaccine) COVID-19 vaccines has been published recently.1 Although the vaccination campaign in the UK is still ongoing, the data from the report gives us some idea of the above issues.
Background of the surveillance report from the UK
The surveillance report from the UK analysed data collected from individuals using a COVID Symptom Study app, which was developed by a health science company ZOE and was launched at the end of March 2020. The research is led by ZOE co-founder, Professor Tim Spector at King’s College London. Data collected is shared with and analysed by King's College London and ZOE research teams.
The reports covered the period from the first day of the vaccine campaign, 8 December 2020, to 10 March 2021. The nationwide vaccination programme in the UK prioritized senior citizens and the most vulnerable groups.2 According to the COVID-19 vaccine monitoring statistics data provided by the NHS,3 by 14th March, at least one dose of vaccine had been given to the adults aged over 50, front-line health and social care workers (those who participated in the ZOE study had a median age of 46.1 years),4 staff working in care homes, clinically extremely vulnerable individuals, and the adults aged 16 to 65 years in an at-risk group.
The BNT162b2 (Pfizer) vaccination was first rolled out on 8 December 2020, while the ChAdOx1 nCoV-19 (Oxford/AstraZeneca) vaccination was first rolled out on 4 January 2021. Both vaccines are two-dose regimens. However, individuals will be given the second dose at 10-12 weeks after the first dose, rather than 21 days as per the guidance of the vaccine manufacturers. By the end of the analysis period, some people already had both doses of BNT162b2 (Pfizer) vaccines.
The COVID Symptom Study app allows self-reporting of systemic and local side effects for individuals who received one or both doses of the BNT162b2 (Pfizer) vaccine, or the first dose of the ChAdOx1 nCoV-19 (Oxford/AstraZeneca) vaccine. Side effects were monitored for the following 8 days after a vaccination. A subset of individuals also reported receiving a test for SARS-CoV-2 infection by either PCR or lateral flow test. The study also compared infection rates in a subset of vaccinated individuals (subsequently tested for SARS-CoV-2 with PCR or lateral flow tests) with infection rates in unvaccinated controls.1
The side effects of both vaccines
During the analysis period, the COVID Symptom Study app received 627,383 reports of individuals being vaccinated: 282,103 received at least one dose of BNT162b2 (Pfizer), while 345,280 individuals reported being vaccinated with one dose of ChAdOx1 nCoV-19 (Oxford/AstraZeneca).
From the self-report system, it seems that systemic (whole body) side-effects were higher in participants who received ChAdOx1 nCoV-19 (Oxford/AstraZeneca). Systemic side-effects were reported by 13.5% and 22.0% of individuals after the first dose and the second dose respectively of BNT162b2 (Pfizer), while 33.7% of individuals receiveing the first dose of ChAdOx1 nCoV-19 (Oxford/AstraZeneca) reported systemic side-effects. The most commonly reported systemic side-effects were fatigue and headache for both vaccines. They were most frequently reported within the first 24 hours after vaccination, and lasted for about 1 day.
The reported local side-effects were more frequent than the systemic side-effects. However, by contrast with the systemic side-effects, local side-effects were more frequent in participants who received BNT162b2 (Pfizer): 71.9% and 68.5% of individuals reported local side-effects after the first dose and the second dose of BNT162b2, respectively, while 58.7% of individuals reported local side-effects after the first dose of ChAdOx1 nCoV-19. The most frequent local side-effects are tenderness and local pain around the injection site, which occurred most often on the day after injection and lasted for about 1 day. The less frequent side-effects include allergic skin reactions such as skin burning, rashes, and red welts on the lips and face, which was reported in 1.7% of 627,383 users across both types of vaccine.
Both systemic side effects and local side effects of both vaccines were more common among individuals with previous SARS-CoV-2 infection than among those without known past infection. After the first dose of BNT162b2 (Pfizer), systemic side effects and local side effects were 2.9 times and 1.2 times as high among individuals with previous SARS-CoV-2 infection than among those without known past infection. Meanwhile, after ChAdOx1 nCoV-19 (Oxford/AstraZeneca) vaccination, systemic side-effects and local side-effects were 1.6 times and 1.4 times as high among individuals with previous SARS-CoV-2 infection than among those without known past infection. Similar findings had been reported before.5,6 It seems that the previous infection leads to a higher immune response, which is reflected by the systemic side-effects, in a subsequent infection.
In line with the above findings, among the individuals (28,207) who reported having two BNT162b2 (Pfizer) doses, a higher percentage of systemic side-effects were being reported in individuals after the second dose. There were 3325 (11.7%) reporting at least one systemic side effect after the first dose, compared with 6216 (22.0%) after the second dose.
Infection rates after the vaccination of both vaccines
The study analysed infection rates at 0–4, 5–11, 12–20, 21–44, and 45–59 days after vaccination. It was found that the infection risk was significantly reduced starting at 12 days after the first dose of BNT162b2 (Pfizer), reaching 69% at 21–44 days and 72% after 45–59 days. For ChAdOx1 nCoV-19 (Oxford/AstraZeneca), the risk of infection was significantly reduced starting at 12 days after the first dose, reaching 60% later on.
Moreover, the data showed that the vaccines were more effective in younger and slimmer people with no more than one illness. For both vaccines, the reduction of infection was more significant in individuals aged 55 years or younger than in individuals older than 55 years; it was also more significant in those without comorbidity than in those with one or more comorbidities, and in individuals with a BMI of less than 30 kg/m2 than in those with BMI of 30 kg/m2 or higher.
The surveillance report showed us that the systemic side-effects of both vaccines, BNT162b2 and ChAdOx1 nCoV-19, are not highly prevalent. And the findings that the efficacy of the two vaccines are more than 60% 12 days after the injection should give us confidence to have vaccination if we have not had one. This should also encourage the individuals to have the second dose in order to get a higher protection from the vaccine.
References
1. C. Menni, K. Klaser, A. May, et al. Vaccine side-effects and SARS-CoV-2 infection after vaccination in users of the COVID Symptom Study app in the UK: a prospective observational study. Lancet Infect Dis., 2021 Apr 27. S1473-3099(21)00224-3. doi: 10.1016/S1473-3099(21)00224-3.
2. COVID-19 vaccination first phase priority groups. NHS website. Updated 23 April 2021. https://www.gov.uk/government/publications/covid-19-vaccination-care-home-and-healthcare-settings-posters/covid-19-vaccination-first-phase-priority-groups
3. COVID-19 vaccination statistics. By NHS. https://www.england.nhs.uk/statistics/wp-content/uploads/sites/2/2021/03/COVID-19-weekly-announced-vaccinations-18-March-2021.pdf
4. V.J. Hall, S. Foulkes, A. Saei, et al. COVID-19 vaccine coverage in health-care workers in England and effectiveness of BNT162b2 mRNA vaccine against infection (SIREN): a prospective, multicentre, cohort study. Lancet. 2021; (published online April 23.)
5. F. Krammer, K. Srivastava, and V. Simon. Robust spike antibody responses and increased reactogenicity in seropositive individuals after a single dose of SARS-CoV-2 mRNA vaccine. medRxiv, 2021; published online Feb 1. doi: https://doi.org/10.1101/2021.01.29.21250653
6. J. Wise. COVID-19: people who have had infection might only need one dose of mRNA vaccine. BMJ, 2021 Feb 2;372:n308. doi: 10.1136/bmj.n308.
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