I love the vaccines approved for use in America, but I love truth even more. So how much of a difference do covid vaccines and boosters make with death and hospitalization rates?
I did not get a flu shot and a covid booster this season because it was expensive and difficult to get.
Gemini says: Recent data from the 2024–2025 respiratory season shows that while the absolute “headline” effectiveness numbers are lower than they were in 2021, COVID-19 vaccines and boosters continue to provide a significant reduction in the risk of the most severe outcomes.
The effectiveness of the latest vaccines is now measured as incremental protection. This means the percentages represent the additional benefit of getting the current shot compared to someone who might already have immunity from older vaccinations or previous infections.
For the 2024–2025 season, the updated vaccines (targeting the JN.1 and KP.2 lineages) have shown the following effectiveness in preventing hospitalization:
Adults 65 and older: The 2024–2025 vaccine is approximately 45% to 46% effective against hospitalization.
Immunocompromised adults: Protection against hospitalization is slightly lower but still significant, at around 40%.
General Adult Population: In a large study on the Moderna updated vaccine, effectiveness against hospitalization was estimated at 53% during the first few months after the shot.
Data on mortality is often harder to track in real-time due to the time lag in reporting, but trends from 2024 and 2025 indicate that vaccines provide the strongest protection against the most fatal outcomes:
Reduction in Death: Recent real-world data suggest that receiving the latest booster can reduce the risk of death by as much as 64% compared to those who have not received the updated dose.
Critical Illness: Studies from the previous year (2023–2024) showed that vaccines reduced the risk of critical illness—defined as death or admission to the ICU—by nearly 70% in the first two months, waning to about 50% over ten months.
The effectiveness of these vaccines is not static. Protection against emergency department visits and mild illness tends to drop off quickly, sometimes falling significantly within 4 to 6 months. However, the protection against death and hospitalization remains much more durable because it relies on “cellular memory” (T-cells) rather than just immediate antibody levels.
One reason the effectiveness numbers look lower now (e.g., 50% vs. the original 95%) is that almost everyone now has some level of baseline immunity. The current “truth” of the matter is that the vaccines are no longer acting on a “blank slate” population; they are providing a necessary “software update” to the immune system to recognize newer, more evasive variants.
