A report on recent measles transmission describes how several imported incidents led to clusters of cases in South Carolina and Washington state, even as public health measures helped limit further spread. The findings also challenge claims that the US measles surge is primarily driven by infections arriving from abroad, pointing instead to domestic transmission in undervaccinated communities.
In the second imported event, a South Carolina resident visited a public place while infected. Four South Carolina residents who had close contact with the person subsequently became ill. Although they were contagious, those four people visited schools, medical facilities, and churches. Nine of their contacts and one person exposed in a public setting then became ill, resulting in a total of 14 clusters between January 15 and February 17.
In the third imported incident, two state residents returned from South Carolina and became ill between January 15 and 16. No additional cases were associated with them. A fourth importation event involved a resident who returned from a trip, became ill, and complied with isolation and quarantine recommendations. No cases were associated with that incident.
In the fifth imported case, a Washington state resident returned from out-of-state travel, came into contact with a close contact, and became ill on January 19. Despite being contagious, he visited schools and medical facilities. Six close contacts developed symptoms, producing a seven-case cluster that lasted from January 19 through January 29. Genomic sequences from five of the cases were nearly identical to the sequence identified in South Carolina.
Officials credited basic public health measures—including quarantine, isolation, and contact tracing—with preventing additional spread of the virus.
Conflict with Kennedy
The study illustrates how easily measles can spread across states as vaccination rates decline. It also conflicts with a talking point from Health Secretary Robert F. Kennedy Jr., a prominent anti-vaccine advocate. Kennedy has downplayed the current measles surge in the United States and strongly rejected suggestions that decades of anti-vaccine misinformation and disinformation are contributing to rising case numbers and declining vaccination rates.
Instead, Kennedy has argued that there is a “global pandemic” and that the United States is “doing better than any other country in the world in controlling the measles outbreak.” Both claims are false. Dozens of countries have lower infection rates than the United States. Neighboring Canada and Mexico are also experiencing substantial increases in cases, but the US surge is not attributed to imports from abroad; it is being driven by domestic spread in undervaccinated communities.
According to data from the Centers for Disease Control and Prevention, 18 of the 4,588 measles cases confirmed in the country this year were reported among overseas visitors. A total of 4,404 cases, or 96 percent, were linked to domestic outbreaks. The source also reports 43 new cases of infectious disease in the United States this year.
Source: arstechnica.com