How many pandemics have there been in the last century?

In the last century, there have been several notable pandemics, including the 1918 influenza pandemic, the 1957 H2N2 influenza pandemic, the 1968 H3N2 influenza pandemic, the HIV/AIDS pandemic beginning in the late 20th century, the H1N1 influenza pandemic in 2009, and the COVID-19 pandemic that started in 2019. Overall, these events highlight the recurring nature of pandemics and their significant impact on global health.