Two weeks back, the Milwaukee Journal Sentinel ran an article that explored the reasons why pertussis — or whooping cough, as it is more commonly known — has resurged in the United States in recent years.

Here in Minnesota, for example, 4,639 confirmed, probable and suspected cases of pertussis were reported in 2012 — the highest number in 75 years. In 2014, the Minnesota Department of Health documented a smaller but still troubling 1,120 cases, and more than 100 have already been identified this year.

As reporters John Fauber and Mark Johnson point out, experts have identified “a complex confluence of factors” that may have led to whooping cough’s comeback: “a safer but weakened vaccine; more surveillance, especially in adults; genetic changes to the bacterium; and a proliferation of wary parents and anti-vaccine websites.”

“And then there is the disease itself, with its remarkable capacity to spread,” they write. “Each case of Ebola is estimated to generate 1.5 to 2 more cases; each smallpox case, 6 to 7 more. A single case of whooping cough, however, generates anywhere from 12 to 17 more. And every three to five years, there is a major outbreak and the numbers spike.”

Misinformed blame

Nowhere do Fauber and Johnson cite any experts telling them that the resurgence of whooping cough in the U.S. can be blamed on unvaccinated immigrants coming over the Mexican border. And for a good reason. There’s no evidence to support that assertion.

Yet, when the Journal Sentinel article was reprinted last week on the popular conservative website the Drudge Report, Fauber and Johnson suddenly found themselves deluged with emails and phone calls claiming that they had deliberately chosen to ignore the “real” cause of whooping cough’s return.

“Reviewing your list of reasons for its reappearance, I couldn’t help but notice that you sold your soul to avoid the wrath of La Raza by not mentioning the flood of unvaccinated illegals crossing the Mexican border,” one Florida reader told the reporters. “Good work, the Hispanic Racists know they have you terrified to tell the truth.”

The facts about rates

So, last Sunday, Fauber and Johnson published a follow-up piece in the Journal Sentinel. Using World Health Organization data, they point out that “vaccination rates in Mexico and Central American countries are comparable and in some cases superior to those in the United States.”

Here, for example, are the WHO rates, as reported by Fauber and Johnson, on whooping cough immunizations for the years 2010, 2011, 2012 and 2013:

Mexico: 95%, 97%, 99% and 83%

Guatemala: 94%, 88%, 96% and 92%

El Salvador: 89%, 89%, 92% and 92%

Nicaragua: 98%, 98%, 98% and 98% 

And here are the rates for the U.S. during those same years: 95%, 95%, 96% and 94%.

A reversal of border shuttings?

“Based on the numbers alone,” write Fauber and Johnson, “America’s neighbors to the south might consider shutting their borders to residents from Colorado, where just 81% of kindergarten children were vaccinated against whooping cough and 82% were vaccinated against measles, according to a CDC report in October.”

“Also, vaccination rates have varied substantially in pockets of California, where the most recent measles outbreak occurred and where they have been recent whooping cough outbreaks,” they add. “A paper found undervaccination rates ranging from 18% to 23% in five geographic clusters.”

“I do not believe undocumented immigrants are a significant contributor to the increase in pertussis rates,” a public health official in New Mexico told the reporters. “In New Mexico, a much bigger contributor would be the children with school vaccination exemptions.”

You can read Fauber and Johnson’s original and follow-up articles on the Journal Sentinel website.