That means almost 13 million babies missed the first of three required injections of a vaccine to protect against the diseases diphtheria, tetanus, and pertussis. It is called the DTP3 vaccination.
An additional 6.6 million infants got that first injection, but failed to get the other two doses last year.
"Since 2010, the percentage of children who received their full course of routine immunizations has stalled at 86 percent," WHO said in a statement on Monday.
"This falls short" of the worldwide immunization coverage target of 90 percent, the statement noted. It said there were no important changes in any countries or areas during the year.
Present immunization levels prevent two to three million deaths worldwide every year from diphtheria, tetanus, pertussis and measles, WHO said. It called routine vaccinations "one of the most successful and cost-effective" public health actions that can be carried out.
One-hundred-thirty of the 194 WHO member states have reached the 90 percent level for DPT3 vaccines. Most unvaccinated infants live in countries where there is conflict or high levels of poverty.
Eight nations had levels below 50 percent for DPT3 shots in 2016. They were Central African Republic, Chad, Equatorial Guinea, Nigeria, Somalia, South Sudan, Syria and Ukraine.
"If we are going to raise the bar" on worldwide immunization coverage, "health services must reach the unreached," said WHO's Jean-Marie OkwoBele. "Every contact with the health system must be seen as" a chance to protect children against disease.
The good news is that WHO reported gains in vaccinations against rubella, a virus that can cause severe birth defects in children. But the vaccine must be given to pregnant women before they give birth.
Around the world, coverage against rubella increased from 35 percent in 2010 to 47 percent in 2016, WHO said. It called the improvement a "big step toward reducing" the condition that results in hearing loss, heart problems, and blindness.
The fight for higher vaccination rates is not just happening in developing nations or those experiencing war. In France, the government passed a measure requiring that by 2018, French parents will have to vaccinate their children against a number of diseases. They include pertussis, measles, mumps, and rubella.
France already requires vaccinations against diphtheria, tetanus, and poliomyelitis. Exceptions are made for infants with a few medical conditions.
The French law is a reaction to the movement against vaccinations in developed countries. In the United States, Britain, and France, the measles vaccination rate has fallen below the 95 percent level. That is the level that stops the spread of the disease.
"Children are still dying of measles," French Prime Minister Edouard Philippe told Parliament. He called that "not admissible" in the homeland of Louis Pasteur, the scientist who discovered vaccines.
I'm Anne Ball.