Photo/Illutration A man receives a COVID-19 booster shot at an Osaka site operated by the Self-Defense Forces. (Pool)

A study of “cross vaccinations” for COVID-19 found that while side effects are more prevalent when different vaccines are used for booster shots, the antibody level also increases.

A panel of experts advising the health ministry on the pandemic announced the results of an interim study on cross vaccinations at a Feb. 18 meeting. It was the first time for the results of a cross vaccination study to be released in Japan.

It looked at differences between patients given a Moderna booster after having had two jabs of the Pfizer vaccine and those who received the Pfizer vaccine three times.

While about 70 percent of those whose third shot was a Moderna vaccine developed fevers in excess of 37.5 degrees, the antibody level, which indicates whether infections can be prevented, was higher as well.

The study analyzed symptoms of 437 medical care professionals for a one-week period after receiving the Moderna booster. The booster dose was half of that given for the first two jabs.

A comparison was made with the 2,626 people who received three Pfizer jabs.

It found that 68 percent of those who received the Moderna booster developed a fever, but the figure was only 39.8 percent for those who got the Pfizer jab.

Younger people developed fevers to a greater extent. The study found that 81.6 percent of those in their 20s who received the Moderna booster developed a fever. This compared with 46.7 percent of those aged 60 and older who developed a fever.

The Moderna booster also led to higher percentages of other symptoms. For example, 93.8 percent felt pain in the upper arm area where the jab was administered, compared to 91.6 percent who received a Pfizer booster.

Lethargy was higher at 78 percent, compared to 69.1 percent for the Pfizer booster, while headaches affected 69.6 percent of patients getting the Moderna booster. Only 55 percent of patients getting a Pfizer shot developed headaches.

The good news for those getting the Moderna booster is that the antibody level increase rises 67.9 times compared with 54.1 times for those getting a third Pfizer jab.

The difference in antibody level was at a statistically significant level. Other studies have also found that cross vaccinations increase the prevention of infection.

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