As recent COVID-19 data from Taiwan’s Centers for Disease Control reveals rising severe cases concentrated among older adults, researchers are exploring whether a natural dietary compound called spermidine could reverse immune aging and enhance vaccine protection in seniors who show weak initial antibody responses.
Current COVID-19 Trends and High-Risk Vulnerability in Taiwan
Recent global data shows that COVID-19 test positivity rates have begun to climb again, driven primarily by Omicron sublineages. According to Taiwan’s Centers for Disease Control (CDC) data, 42 domestic severe cases were added between July 21 and 27, up from 25 cases the previous week, alongside two new deaths during the same period. Among the newly reported severe cases, 69 percent involved individuals aged 65 or older, 83.3 percent had chronic conditions, and 83.3 percent had not received the current season’s vaccine.
A similar concentration appears in mortality figures. Between October 2025 and July 27, 2026, Taiwan recorded 25 domestic COVID-19 deaths. Of those, 80 percent were individuals aged 65 and older, 88 percent lived with chronic illnesses, and 92 percent had skipped the seasonal vaccine. Medical consensus indicates that receiving a current booster offers clear benefits for people over 65—particularly in lowering the risks of pneumonia, hospitalization, intensive care unit admission, and death—especially when complicated by conditions like diabetes, cardiovascular disease, kidney disease, lung disease, or cancer. For healthy adults around age 40, however, the absolute benefit remains much lower due to inherently low baseline severe case rates.
Some individuals worry about potential downsides to receiving the current season’s vaccine. mRNA vaccines carry very rare risks such as myocarditis or pericarditis, with an incidence of several tens of cases per 100,000 people, though varying across studies and with most patients recovering well.
When considering individual immunity after past vaccinations, human immunity is divided into three layers. Circulating neutralizing antibodies are the easiest to measure, peak two to four weeks after vaccination, drop significantly over three to six months, and usually dwindle to small amounts after a year. Memory B cells can persist for many years; although they do not offer immediate protection, they rapidly differentiate into plasma cells to manufacture large quantities of antibodies if a virus invades again, though significant viral mutations can reduce antibody recognition capability. T cell immunity is what truly prevents severe illness, lasting for many years and retaining its protection against severe disease even if the virus mutates slightly, though its ability to prevent infection drops quickly.
Cellular Aging and the Mechanism of Spermidine
While vaccine effectiveness can wane, the primary barrier in older populations involves the aging of the immune system itself. As people age, immune efficiency declines, making it harder to fight infections or mount full responses to vaccines. This process, known as immune aging, causes weaker protection after vaccination, a phenomenon called vaccine response insufficiency, which the medical community is eager to resolve.
Spermidine occurs naturally in foods such as wheat germ, mushrooms, and aged cheese. It functions as a natural polyamine that the body can synthesize or absorb through diet, though internal levels drop with age. Its primary role is promoting autophagy—the cellular cleaning and recycling system that clears damaged proteins and aging organelles.
Clinical Trial Findings on Immune Activation
The pilot trial enrolled 40 healthy adults aged 65 and older who had completed their third COVID-19 vaccine dose about two months prior (with a median of 58 to 69 days). Researchers evaluated baseline antibodies, neutralizing capacity, memory B cells, and cellular aging indicators before randomly assigning participants in a double-blind, placebo-controlled design to receive either six milligrams of supplemental spermidine daily or a placebo for 13 weeks.
Baseline analysis revealed that about one-quarter of the participants maintained weak antibody responses despite three vaccine doses, classifying them as vaccine non-responders. These individuals showed distinct immune aging markers, including increased DNA damage, elevated cellular senescence markers like p16 and p21, and insufficient autophagy.
After 13 weeks of daily spermidine supplementation, those original non-responders experienced significant increases in anti-Spike antibody concentrations, enhanced neutralizing capabilities against multiple SARS-CoV-2 variants, improved memory B cell function, restored autophagy, and reduced senescence markers. By contrast, participants who started with normal vaccine responses showed relatively limited improvement.
Natural food sources of spermidine include wheat germ, soybeans, fermented soy products like natto and miso, mushrooms, whole grains, peas, and aged cheeses such as Parmesan and Cheddar. However, because the trial relied on daily purified six-milligram supplements, and because older adults often experience reduced appetite and lower internal synthesis, whether dietary adjustments alone can match these immunological effects remains to be confirmed by larger clinical trials.
The supplements used in the trial appeared safe and well-tolerated, with researchers noting no treatment-related adverse reactions. Because this was a pilot trial with a relatively small number of participants, future larger studies are still required to confirm whether spermidine can reliably and steadily improve vaccine responses, and whether it has the same effect on other vaccines such as the seasonal influenza vaccine.
To navigate this current minor wave of infections, readers can maintain a normal lifestyle while high-risk individuals receive a booster for the current season’s vaccine, wear masks reasonably in crowded and enclosed spaces, and seek medical care early if symptoms develop so that qualified professionals can prescribe antiviral medications without delay.
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