TOKYO >> Earlier this year, an outbreak of rubella began to sweep Japan.

More than 1,300 people — mainly men in their 30s and 40s — had been diagnosed with the virus as of early May.

But why should such a specific demographic fall victim to rubella?

From 1977 to 1995, the government mandated that only female junior-high-school students receive rubella vaccines. From 1995 onward, boys as well as girls between 12 and 90 months of age became subject to the vaccination, but some individuals, especially boys who were in junior high at the time, fell through the cracks. Vaccination coverage among that group is estimated to hover at about 50%, according to a 2002 report published by the health ministry.

This is just one of a number of governmental vaccination policies that led Japan to earn itself a reputation as a “vaccine backwater.”

Japan gained that name from the mid-1990s to the early 2000s because it barely introduced new vaccines, widening the so-called vaccination gap between itself and other countries.

The vaccination-gap decade was followed by a rush to close it, and the country’s vaccination policy has seen major changes over the years. Yet some believe there are still systemic gaps in governmental policy that have left the nation vulnerable to small, sporadic outbreaks of preventable diseases.

“In terms of vaccination policy, Japan is not a backwater anymore, but it isn’t a leading nation either,” said Tetsuo Nakayama, a professor at Kitasato Institute for Life Sciences.

Today, the government’s list of recommended vaccinations has been updated and is in keeping with that of the World Health Organization.

But a closer look at the list reveals why Japan isn’t a leader in vaccinating its population.

The list is separated into two shorter lists — one of “routine” vaccinations that can be subsidized by the government, and recommended “voluntary” vaccinations for which parents must pay.

“Having a list of ‘voluntary’ vaccinations sends the message that these vaccinations aren’t really necessary,” said Hiroyuki Moriuchi, a Nagasaki University professor, and that affects vaccination rates.

Though rates in Japan for routine vaccines are among the highest in the world, in some cases reaching north of 95%, rates for voluntary vaccines are much lower.

For example, vaccination rates in 2011 for haemophilus influenzae type b and pneumococcus, which were voluntary at the time, were 53% and 43%, respectively, for 18-months-olds, while the figure in the U.S. was 90% and 92%, according to a 2014 report published by University of Hawaii researchers.

Yet vaccination rates have soared since both vaccines were put on the routine list, with coverage reaching more than 97% for children younger than 12 months old, according to a report in 2017 by the National Institute of Infectious Diseases.

However, some believe Japan should be scaling back on encouraging everyone to get vaccinated.

“Japan is not a vaccination backwater,” said Hiroko Mori, former head of the infectious diseases department at the National Institute of Public Health, and author of the “Guidebook on Vaccines for Children and Parents.”

Vaccination policy in Japan should be changed so that “those who want to get immunized can get immunized, and those who don’t want to aren’t forced into it,” Mori said, adding that the current discussion lacks nuance and pressures people to get vaccinated.

“Some of these diseases may have been devastatingly fatal in the past, but we live in a day and age where they aren’t nearly as fatal … Especially with the high standards of health here, it’s not necessary for everyone to be forced into getting immunized against all such diseases,” she said.

Instead, vaccinations should be done sparingly and effectively, such as immunizing pregnant women against rubella to prevent the birth of infants with congenital rubella syndrome, she said.

Mori believes the government should make all vaccines voluntary and free of charge, so that citizens can get the vaccinations they want, when they want.

The WHO, however, states that it is important, even with advanced nations’ higher levels of hygiene, sanitation and nutrition, to maintain optimum rates of immunization, or “herd immunity,” to prevent the diseases from returning.

The current system of separating routine from voluntary vaccines stems from the government’s bitter history of losing lawsuits to those who suffered from adverse effects of the vaccine.

In one emblematic case from 1989, Japan introduced the MMR (mumps, measles and rubella) vaccine, but after reports of adverse side effects the public raised concerns, and it was discontinued in 1993.

Although the side effects themselves were in some cases relatively severe, they were not widespread, said Moriuchi. But the government overhauled the Vaccination Act in 1994, making vaccinations an individual responsibility, shifting responsibility from the government onto municipalities and individuals, and it was cautious about introducing and promoting new vaccines.

Nakayama believes that individuals need to educate themselves.

On top of structural, government-level changes, “what’s most important is for individuals to cultivate a good sense of judgment based on sound, scientific knowledge, so that they will be able to differentiate accurate information from misinformation,” he said.