Black and white images of children wearing leg braces give a false sense of security that forgotten diseases like polio are gone, but many seem to be slowly creeping back.

Cases of polio, whooping cough and other diseases are documented across the world, causing renewed warnings and calls for vaccination.

“We live in a global village,” said Henry Anyimadu, MD, chief of infectious disease for Hartford HealthCare’s Central Region. “Diseases that evolve in other parts of our world easily get around through international travel.”

> Related: New York Reports First U.S. Polio Case Since 2013

Making a comeback

He said some forgotten diseases are returning due to:

“In the case of polio, individuals and communities that are not vaccinated or have low vaccination rates have the highest risk of infection,” Dr. Anyimadu said.

These reasons could also fuel epidemics, especially in areas with low vaccination rates, he said.

“Unvaccinated or partially vaccinated people can drive epidemics by shedding the virus and infecting other susceptible people,” he said.

As an example, the Centers for Disease Control and Prevention (CDC) determined that two doses of inactivated polio vaccine, available in the U.S., offers 90% protection against all three types of the polio virus.

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Lingering viruses

Other diseases that have not disappeared entirely, Dr. Anyimadu said, include:

  • Whooping cough. “Outbreaks continue to occur with intermittent peaks. 27,550 cases of whooping cough in the U.S. were reported to the CDC in 2010. In 2012, cases peaked at 48,277. In 2019, there were 18,617 cases,” he said. Worldwide, he noted there are about 24.1 million cases, and 160,700 deaths, each year.
  • Tuberculosis (TB). During the pandemic, reported cases dropped 20%, and remained 13% lower in 2021 than pre-pandemic. “This decline could be from true reduction in TB disease, as well as missed or delayed TB disease diagnoses due to the pandemic,” Dr. Anyimadu said, adding that 7,860 cases were reported in the U.S. in 2021.
  • Plague. Rare in developed countries, there are 16 cases this year in the U.S., with about 3,000 cases globally. Vaccine and better living conditions have virtually squashed plague, which is spread by fleas carried on rats.
  • Rubella. The U.S. in 2015 became the first region to use vaccination to eliminate this virus, which passes birth defects to unborn babies. Infection remains in countries with low immunization rates, including Africa and Asia.
  • Leprosy. Multi-drug therapy in the 1970s helped decrease global cases to about 200,000 in 2013. The disease, which causes damage to nerve and skin cells, is still a problem in parts of India, Brazil and Indonesia.
  • Scarlet fever. Improved living conditions and antibiotics helped reduce the prevalence of this disease, caused by bacteria spread through sneezing and coughing. Global outbreaks – such as more than 14,000 cases in 2014 in the United Kingdom – continue.