A T cell discovery, “hachimoji” DNA, a new species of human, and mounting fears of espionage rounded off the list this year.

The public health emergency has spurred a mass vaccination campaign.

Two studies present biological evidence that measles infections in unvaccinated children wipe out immune memories of other pathogens, putting the kids at risk of other deadly diseases.

The number of measles cases this year is already more than all of the cases reported in 2018.

Mathematical models reveal that current vaccination rates in Texas schools could pave the way for the virus to spread to hundreds of people.

The forecast for upcoming outbreaks failed to foresee the cluster of infections currently affecting Brooklyn.

Health officials have asked students and staff potentially exposed to the virus and who either have not been vaccinated or cannot verify immunity to stay home.

There are now more cases of measles in America than in any year since the disease was eradicated nearly 20 years ago.

So far this year, 465 infections have been reported, with numbers approaching their highest since measles returned to the country.

Most people who contracted the disease were unvaccinated and some state legislatures are now considering whether to curtail nonmedical vaccine exemptions.

The World Health Organization reports that a number of countries are experiencing “sizeable” numbers of the infection due to a failure to vaccinate.

The outbreak has infected 50,000 people and killed 300, most of them children, since cases began to crop up in October 2018.

Most of the 34 patients are under 10 years old, and almost all have been confirmed as unvaccinated against the virus.

In one county alone, more than 100 cases have been confirmed since October.

The WHO reports more than 41,000 cases in the region in the first half of 2018.

The increase is associated with travel to Europe, where large outbreaks are occurring.

The increase is attributed to a drop in immunization rates.

Health officials announce that measles is no longer endemic to any region in the Americas, thanks to widespread vaccination.

The eradication of smallpox set the standard for the global elimination of a devastating infectious disease. Will the ongoing polio and guinea worm campaigns be as successful?