All COVID-Infected at Health Conference Were Vaccinated: Study

Health care workers prepare COVID-19 vaccines in Berlin, in a Feb. 10, 2022 file image. Sean Gallup/Getty Images

Every person known to be infected with COVID-19 after attending a 2022 health conference in Germany was vaccinated, according to a new study.

All people who reported testing positive for COVID-19 said they had received at least two doses of a COVID-19 vaccine.

While about 4,462 people attended the conference in Berlin in the fall of 2022, just 1,355 filled out a survey and only about half of those were tested after the conference, researchers said in the new paper, published on June 13 by JAMA Network Open, a journal from the American Medical Association.

Of the people who filled out the survey and were tested after the conference, 109, or 14 percent, tested positive for COVID-19.

All 109 were vaccinated.

Just 19 had evidence of prior COVID-19 infection.

In comparison, of the people who filled out the survey and tested negative after the conference, 98 percent were vaccinated and 62.5 percent had proven prior COVID-19.

Factors

That means that a person’s vaccination status “was not associated with SARS-CoV-2 infection during the congress,” Dr. Alaa Din Abdin of Saarland University Medical Center UKS and the other authors wrote. SARS-CoV-2 is the virus that causes COVID-19.

On the other hand, prior infection was “significantly associated” with testing negative, and staying in private accommodation versus a hotel was associated with a higher infection rate.

The conference in question was the 122nd Annual Congress of the German Society of Ophthalmology, from Sept. 28 to Oct. 2, 2022. People attended the conference in person for the first time in three years.

Researchers found a higher rate of infection, 8 percent among those who went to get tested after the conference, than previous studies. That might stem from the protection from the vaccines declining following the late 2021 emergence of Omicron, they said.

“This higher rate could be because the congress took place during the Omicron surge, which was locally and temporally different compared with the variants in other studies,” they said, adding later that “the Omicron variant had a much higher transmission rate and lower vaccine efficacy due to immune escape of the new subtype.”

Other Conferences

A survey of attendees of a different conference, hosted in the United States by the U.S. Centers for Disease Control and Prevention (CDC), found recently that all the people who responded and tested positive had received at least one dose of a COVID-19 vaccine.

Of the 1,800 people who attended the conference in person, 1,443 responded to a survey. Nearly all were vaccinated. Of the respondents, 181 reported testing positive, about half of whom had known prior COVID-19.

That conference was held at a hotel in April in Atlanta, where the agency is headquartered.

None of the people who reported testing positive said they had been hospitalized.

The CDC claimed that the results “underline the importance of vaccination for protecting individuals against severe illness and death related to COVID-19.”

U.S. researchers, in an earlier JAMA Network Open paper, described the results of a survey filled out by people who attended the Academic Surgical Congress in February 2022.

Of the 1,617 attendees, including some who attended virtually, 681 responded to the survey. All of the 546 respondents who attended in person said they were fully vaccinated, or had received at least two doses of the Moderna or Pfizer vaccine or the single-shot Johnson & Johnson vaccine. It wasn’t clear how many were tested for COVID-19.

Ten of the in-person respondents, all of whom were vaccinated and had received a booster, said they tested positive for COVID-19 within a week of the conference. Seven had to miss work and four developed symptoms, but none were hospitalized.

Another set of American researchers reported results from a survey of people who attended the Society for Asian Academic Surgeons’ annual meeting in Chicago in September 2021. Of the 220 participants, 91 responded to the survey. Of those, 71 attended in person, and just one hadn’t been fully vaccinated.

Of the people who attended in person, 11 were tested for COVID-19. All tested negative.

“It is possible that there were positive cases among individuals who were not tested, though none of these participants reported development of symptoms,” the researchers said.

Recent Data

The vaccines were originally promoted as being highly effective against infection and, in some quarters, transmission, but a growing body of data show they do neither well, particularly after Omicron emerged.

Three doses of Moderna’s vaccine turned negative against infection over time, one study found, with similar results from several other papers and a dataset from the CDC.

A meta-analysis published in May found that the effectiveness of the vaccines against Omicron “rapidly wanes over time,” going lower than 20 percent against infection after six months.

While officials have shifted to encouraging people to get vaccinated to protect against severe COVID-19, shielding against hospitalization, widely seen as a marker for severe illness, has also dropped sharply in recent months.

The protection against hospitalization or death dropped below 50 percent after just four weeks, according to one paper. And the protection against hospitalization went negative after some time, with a booster only temporarily helping, according to CDC data presented this month.