TOKYO: With more and more people receiving their COVID-19 vaccine doses in Japan, sales of fever and pain relievers are also expanding sharply.

The number of people taking such drugs after experiencing negative reactions from novel coronavirus vaccines is believed to be rising.

According to Tokyo-based research firm Intage Inc., sales of antipyretic analgesics increased 50 percent from a year earlier in late June, when COVID-19 vaccinations at workplaces started.

A survey by Japan’s health ministry found that many people who received coronavirus vaccines experienced negative reactions such as pain in the area of injection, overall tiredness, headaches and fever. Nearly 80 percent of those who were given their second shot of the vaccine developed by Moderna Inc. of the United States ran a fever of 37.5 degrees Celsius or higher.

Intage found that sales of medicines to relieve pain and fever started to rise around May, when vaccinations among elderly people started in earnest. In particular, sales increased sizably for products containing acetaminophen, which helps reduce pain and fever, Intage analyst Toshimitsu Kiji said.

Acetaminophen is prescribed by many doctors to people receiving COVID-19 vaccinations. Over-the-counter drugs using acetaminophen are also available from Lion Corp. Alinamin Pharmaceutical Co. and other companies.

Lion saw sales of its drugs relieving pain and fever rise 20 percent in January-June. Sales of Alinamin products shot up 40 percent in June, with some of them running out of stock temporarily.

Following such a situation, the health ministry said in mid-June that people can also take ibuprofen and loxoprofen, which also help ease pain and fever, for coronavirus vaccines’ side effects.

Sales of drugs with loxoprofen from Daiichi Sankyo Healthcare Co. grew 50 percent in the final week of July.

As Japan is seeing a resurgence in coronavirus cases, the end to the pandemic is nowhere in sight.

With COVID-19 vaccines expected to reach more people, Lion President Masazumi Kikukawa said that he expects the sharp increase in demand for pain and fever relievers will continue through the second half of 2021.

“We’ll deal with the situation by preparing the best possible production system,” he added.