You are presented with a paragraph from a COVID-19 literature. Classify the topics of this piece of text by choosing from the following categories:

- Epidemic Forecasting: The content relates to predictions about the spread of COVID-19.
- Treatment: The paragraph discusses therapeutic methods or medication for COVID-19.
- Prevention: The content covers measures to prevent the spread of COVID-19.
- Mechanism: The paragraph explains the biological mechanisms of the virus.
- Case Report: The content is a report of a COVID-19 case.
- Transmission: The paragraph discusses how COVID-19 is transmitted.
- Diagnosis: The content is about diagnosing COVID-19 in individuals.

Your classification should be provided as an element within a JSON array. The array should be formatted with topics enclosed in double quotes and separated by commas, following the JSON format, for example: ["Topic1", "Topic2", ...]. Include all applicable topics within the array. Your output should be a valid JSON array, and no additional text should be included in your response.

Article:

Background: Two FDA-authorized mRNA COVID-19 vaccines, BNT162b2 (Pfizer/BioNTech) and mRNA-1273 (Moderna), have demonstrated high efficacies in large Phase 3 randomized clinical trials. It is important to assess their effectiveness in a real-world setting. Methods: This is a retrospective analysis of 136,532 individuals in the Mayo Clinic health system (Arizona, Florida, Iowa, Minnesota, Wisconsin) with PCR testing data between December 1, 2020 and April 20, 2021. We compared clinical outcomes for a vaccinated cohort of 68,266 individuals who received at least one dose of either vaccine (nBNT162b2 = 51,795; nmRNA-1273 = 16,471) and an unvaccinated control cohort of 68,266 individuals propensity-matched based on relevant demographic, clinical, and geographic features. We estimated real-world vaccine effectiveness by comparing incidence rates of positive SARS-CoV-2 PCR testing and COVID-19 associated hospitalization and ICU admission starting 7 days after the second vaccine dose. Findings: The real-world vaccine effectiveness in preventing SARS-CoV-2 infection was 86.1% (95% CI: 82.4-89.1%) for BNT162b2 and 93.3% (95% CI: 85.7-97.4%) for mRNA-1273. BNT162b2 and mRNA-1273 were 88.8% (95% CI: 75.5-95.7%) and 86.0% (95% CI: 71.6-93.9%) effective in preventing COVID-19 associated hospitalization. Both vaccines were 100% effective (95% CIBNT162b2: 51.4-100%; 95% CImRNA-1273: 43.3-100%) in preventing COVID-19 associated ICU admission. Conclusions: BNT162b2 and mRNA-1273 are both effective in a real-world setting and are associated with reduced rates of SARS-CoV-2 infection and decreased burden of COVID-19 on the healthcare system.
["Treatment"]