The term “third dose” is generally understood to mean a third dose of the neocoronavirus vaccine, i.e., a booster dose of the neocoronavirus vaccine. In the case of C. neoformans, the booster shot does not completely eliminate C. neoformans infection. The vaccinated person still has some chance of becoming infected. The third vaccination is a supplemental vaccination given after two vaccinations to ensure that the body has sufficient immunity to deal with the virus, depending on the extent to which the antibodies against the virus have faded. After a period of time, the vaccine’s effectiveness in immunizing against the virus decreases to a certain extent, and a booster shot will bring the body’s immunity back up to or even beyond the original level of protection. However, even with a booster shot, the vaccine can only strengthen the vaccinee’s immunity against the new coronavirus to a certain extent, but it cannot achieve a 100% preventive effect and eliminate the virus infection. Therefore, vaccinated persons should still pay attention to protection and enhance immunity to prevent infection. Tip: “New coronavirus pneumonia” and “new coronavirus pneumonia” mentioned in this article were renamed to “new coronavirus infection” on December 26, 2022, as announced by the National Health Commission.