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:

As of 1 May 2021, there have been 152 661 445 Covid-19 cases with 3 202 256 deaths globally. This pandemic led to the race to discover a vaccine to achieve herd immunity and curtail the damaging effects of Covid-19. This study aims to discuss the most recent WHO-approved Covid-19 vaccine subtypes, their status and geographical scheduled updates as of 4 May 2021. The keywords "Covid-19, Vaccines, Pfizer, BNT162b2, AstraZeneca, AZD1222, Moderna, mRNA-1273, Janssen, Ad26.COV2.S" were typed into PubMed. Thirty Two relevant PubMed articles were included in the study. The vaccines discussed are Pfizer/BNT162b2, Moderna Vaccine/mRNA1273, AstraZeneca/AZD122/ChAdOx1 n-CoV-19 and the Janssen vaccines/Ad26.COV2.S, as well as their platforms, trials, limitations and geographical distributions. As of 16 May 2021, the number of countries that have approved the use of the following vaccines is Pfizer in 85, Moderna in 46, Oxford/AstraZeneca in 101, and Janssen in 41.
["Treatment"]