History of vaccines' detrimental side effects causes safety concerns in Japan

History of vaccines' detrimental side effects causes safety concerns in Japan

By Akihiko Kano / Yomiuri Shimbun Staff Writer

The first COVID-19 inoculations were administered in Japan on Feb. 17, but the general public is skeptical about whether the vaccine is safe.

While vaccines are seen by many as an effective measure to prevent the spread of coronavirus infections, concerns over side effects -- which have become a social problem -- have created deep-seated anxiety about vaccinations in the nation.

This column explores the steps that need to be taken to gain the public's trust and promote inoculation by looking at the history of vaccinations in Japan.

-- Lingering concerns

Local governments in the Tokyo metropolitan area on Feb. 15 began phone consultation services regarding COVID-19 vaccinations, and they have received many inquiries since that day over concerns about the safety of inoculations and over possible side effects.

According to overseas data, the Pfizer-BioNTech vaccine being used in Japan reduces the risk of developing the symptoms to one-twentieth of those who do not receive the inoculation, and serious side effects are reported to be rare.

Yet some people are worried because the vaccine is a new type that uses the genetic information of the virus and the manufacturer developed the vaccine quite quickly.

According to an international poll conducted at the end of January about the intention to receive a COVID-19 vaccine, 64% of respondents in Japan said they "definitely want to receive a vaccine" or "somewhat want to be vaccinated," the fourth-lowest rate among the 15 countries surveyed.

Of the respondents who did not want to be vaccinated, 66% of Japanese said they "fear side effects," the highest number among the 15 nations.

-- Downsides remain

One of the reasons behind the cautious attitude regarding vaccination in Japan is a history of side effects, which in some cases became a social problem that led to a series of legal actions.

Many Japanese died of infectious diseases after World War II. In 1948, the government established the Immunization Law -- which included penalties -- that required vaccination against 12 diseases, including whooping cough.

However, immediately after the law was enacted, many children in Kyoto and Shimane prefectures who had received diphtheria vaccinations complained of abnormalities. More than 80 children died of diphtheria poisoning after inoculation.

"This was one of the worst vaccination accidents in the world," said Osaka City University Prof. Yosuke Tezuka, an expert on the history of vaccinations.

The government was not held responsible because it was caused by errors in the manufacturing process. Therefore, the incident did not make any changes in vaccination policy.

Vaccines contributed to a decrease in the number of deaths due to infectious diseases, but inoculation-related health hazards began to garner attention.

Vaccinations became a major social problem in the nation when lawsuits over damages caused by inoculations against smallpox and other diseases were filed in the 1970s.

The World Health Organization declared smallpox eradicated in 1980 thanks to highly efficient vaccines, and there have been no new outbreaks of the disease in Japan since 1956.

However, encephalitis occurred as a side effect after vaccination in one out of 100,000 to 500,000 people, and some children became seriously disabled as a result. After about 20 years of litigation, a court ruling forced the government to take responsibility.

-- Government turning point

The combined MMR vaccine against measles, mumps and rubella, which was introduced in Japan in 1989, caused many cases of aseptic meningitis with a high fever and other symptoms in children who received the inoculation.

The government initially estimated the frequency of side effects to be "about one in 100,000 to 200,000," but it was eventually discovered that the rate was "about one in 1,200," forcing the government to suspend vaccination in 1993.

It was also learned that the manufacturer had changed the manufacturing process without the government's permission, which was considered problematic.

"These events led to a growing distrust of vaccinations among the public," Tezuka said. "It became a major turning point for the vaccination policy."

In 1994, the government revised the Immunization Law, easing the requirement for vaccination from "mandatory" to "duty to make an effort" for citizens.

The government also changed the wording of the provisions of the law from "mass vaccination" to "individual vaccination," showing a change in stance toward each person's own judgment.

With the government taking a reluctant position toward vaccinations, manufacturers lost interest and no longer develop vaccines on a large scale. This has led to a decline in their development capabilities over time.

Amid the spread of the coronavirus, domestic vaccine development has lagged far behind those made in Europe and the United States.

-- Risk aversion

While there are cases of side effects overseas, some experts have said the Japanese have particularly higher tendency to avoid risks than others.

"Although there is the risk of side effects occurring at a certain frequency due to the vaccines, I want people to understand that the benefits of vaccination outweigh the risks," said Nobuhiko Okabe, chief of the Kawasaki Institute for Public Health and an expert on measures against infectious diseases.

"In order to bring the coronavirus under control as soon as possible, we must quickly send out accurate information and gain the public's trust in the vaccines."

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Yomiuri Shimbun file photo

Plaintiffs and their lawyers taking part in an MMR vaccine lawsuit walk to the entrance of the Osaka High Court in April 2006.

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