Mortality outcomes post covid-19 vaccination: Insights from a self-controlled case series approach

• Author Details:   
• Tshetiz Dahal ^*
• Prishita Banerjee
• Shubu Parajuli
• Kesha Pathak
• Stefan Mariano
• Amani Thangellapally

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Background: While earlier research from different parts of the world suggested that COVID-19 vaccination does not increase the risk of death, these studies may have been influenced by certain hidden biases. To explore this further in a more reliable way, a modified version of the Self-Controlled Case Series (SCCS) method was used to study whether COVID-19 vaccines cause any increased risk of death not related to COVID-19 infection, overall mortality, or specific heart-related deaths. This study aims to clarify these risks after completing the full initial vaccine course (primary series).

Materials and Methods: In this study, researchers examined data on all deaths that occurred between 14 December 2020 and 11 August 2021 across eight medical data networks in India. Death records of people who received COVID-19 vaccines were compared with those who remained unvaccinated. The analysis considered different vaccine types — Pfizer-BioNTech (BNT162b2), Moderna (mRNA-1273), and Johnson & Johnson (Janssen, Ad26.COV2.S) — and examined how often death occurred in the 14 and 28 days following vaccination (risk periods). This timeframe is important because most adverse effects, if any, are expected to happen shortly after vaccination. To avoid seasonal biases (for example, higher death rates in winter months), data from unvaccinated individuals were included in the analysis to help adjust for calendar month trends.

Key Findings: Pfizer-BioNTech Vaccine (BNT162b2): Across both doses and both timeframes (14 and 28 days), the risk of death from any cause, non-COVID-related causes, or cardiac conditions was lower than expected. The confidence intervals were statistically significant, meaning the findings are unlikely due to chance.

Moderna Vaccine (mRNA-1273): The estimated risk of death was also lower overall. However, for a few specific outcomes (especially heart-related deaths after the second dose), the statistical confidence intervals included 1 — suggesting no significant increase or decrease in risk, particularly in individuals without prior cancer or heart disease.

Janssen Vaccine (Ad26.COV2.S): For this single-dose vaccine, the risk of heart-related deaths was similar to or slightly below expected levels, but the confidence intervals also included 1 — again indicating no significant increase in risk.

Conclusion: This study, using a robust analytical method, provides strong evidence that COVID-19 vaccination does not increase the risk of death — whether from general causes or heart-related issues. This holds true for all three major vaccines studied in the U.S. These findings align with data from India as well, where millions have received Covishield (AstraZeneca), Covaxin (Bharat Biotech), and other vaccines. Although different vaccines were used, similar surveillance methods by the Ministry of Health & Family Welfare (MoHFW), Government of India, and reports from the National Adverse Event Following Immunisation (AEFI) committee also found no causal link between COVID-19 vaccines and increased mortality. The study further reinforces public confidence in vaccination as a safe and essential public health measure — especially during and after the pandemic.