pfizer vaccine side effect after first dose

PFIZER VACCINE SIDE EFFECT AFTER FIRST DOSE SERIES

The English National Immunisation (NIMS) Database of COVID-19 vaccination includes data on vaccine type, date and doses for all people vaccinated in England. Therefore, detailed assessments of potential neurological adverse events associated with COVID-19 vaccines and infection are urgently needed. However, case reports and surveillance studies are limited by small numbers, as well as potential selection and recording biases. Furthermore, surveillance studies have found a possible link between severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection and neurological events, including Guillain–Barré syndrome and myelitis 12, 13. Since the start of large-scale vaccine programs across the world, additional case reports have linked other neurological adverse events to COVID-19 vaccination, including Guillain–Barré syndrome 9, 10, 11.

One case of transverse myelitis was considered to be possibly causally related to the vaccine, and an association of rare neuroinflammatory side-effects with ChAdOx1nCoV-19 could not be ruled out. These cases triggered two temporary study pauses, including careful regulatory review by the UK’s Medicines and Healthcare Products Regulatory Agency (MHRA). Furthermore, two cases of transverse myelitis were identified in the treatment arm during ChAdOx1nCoV-19 clinical trials 3. These findings have prompted the United Kingdom, several European countries and two Canadian provinces to limit the use of the ChAdOx1nCoV-19 vaccine or restrict its use pending further risk–benefit analysis in those at low risk of severe outcomes from infection. The increased risk of cerebral venous sinus thrombosis following the ChAdOx1nCoV-19 vaccine is an example of a rare adverse neurological event 7, 8. Therefore, the identification of such rare adverse events is now a global scientific priority.

However, the clinical trials were underpowered to detect rare adverse events 3, 4 that are important for ongoing risk–benefit evaluations of these vaccines and for informing post-vaccination clinical practice. Several vaccines including ChAdOx1nCoV-19 and BNT162b2 are approved for use in multiple countries and these have been shown to reduce COVID-19 infections, transmissions, hospitalizations and deaths in randomized controlled trials and real-world effectiveness studies 1, 2, 3, 4, 5, 6. The coronavirus disease 19 (COVID-19) pandemic has seen the development and deployment of vaccines at an unprecedented speed and scale. In summary, although we find an increased risk of neurological complications in those who received COVID-19 vaccines, the risk of these complications is greater following a positive SARS-CoV-2 test. Overall, we estimated 38 excess cases of Guillain–Barré syndrome per 10 million people receiving ChAdOx1nCoV-19 and 145 excess cases per 10 million people after a positive SARS-CoV-2 test. There was a substantially higher risk of all neurological outcomes in the 28 days after a positive SARS-CoV-2 test including Guillain–Barré syndrome (IRR, 5.25 95% CI: 3.00–9.18). An independent Scottish cohort provided further support for the association between ChAdOx1nCoV and Guillain–Barré syndrome (IRR, 2.32 95% CI: 1.08–5.02 at 1–28 days).

There was an increased risk of hemorrhagic stroke (IRR, 1.38 95% CI: 1.12–1.71 at 15–21 days) with BNT162b2. There was an increased risk of Guillain–Barré syndrome (incidence rate ratio (IRR), 2.90 95% confidence interval (CI): 2.15–3.92 at 15–21 days after vaccination) and Bell’s palsy (IRR, 1.29 95% CI: 1.08–1.56 at 15–21 days) with ChAdOx1nCoV-19.

PFIZER VACCINE SIDE EFFECT AFTER FIRST DOSE SERIES

We undertook a self-controlled case series study to investigate hospital admissions from neurological complications in the 28 days after a first dose of ChAdOx1nCoV-19 ( n = 20,417,752) or BNT162b2 ( n = 12,134,782), and after a SARS-CoV-2-positive test ( n = 2,005,280). Emerging reports of rare neurological complications associated with COVID-19 infection and vaccinations are leading to regulatory, clinical and public health concerns.

Pfizer vaccine side effect after first dose