Three doctors from the Miller School of Medicine joined administrators from the Centers for Disease Control and Prevention to talk about these rare cases, effective treatments, and the viral variants that can cause them.
Although it is extremely rare, some people who have been vaccinated against COVID-19 are still able to contract the virus in what is called a “breakthrough” case. And at the University of Miami’s Miller School of Medicine, doctors are paying close attention to this small subset of patients and trying to understand how and why some people are more susceptible to the disease.
To share their findings, three doctors from the Miller School of Medicine recently joined two doctors from the U.S. Centers for Disease Control and Prevention (CDC) to talk about these groundbreaking cases and the best ways to treat them. Dr Lilian Abbo, Professor in the Division of Infectious Diseases at the Miller School; Dr Shweta Anjan, Assistant Professor in the Division of Infectious Diseases; and Dr David Andrews, associate professor in the Department of Pathology and Laboratory Medicine, spoke to more than 600 infectious disease physicians last week as part of a weekly videoconference hosted by the CDC and the Infectious Disease Society of America.
Dr Emily Koumans, head of the CDC’s clinical diseases and health systems team for the COVID-19 response, detailed the national picture of groundbreaking cases. Koumans said that since April, more than 10,000 vaccinated U.S. residents have contracted COVID-19. Of these people, 63 percent were women and the median age was 58. Additionally, she said 27 percent of those patients were asymptomatic, 10 percent were hospitalized and 2 percent died. Although the CDC was unable to sequence test results for just over 5% of these breakthrough cases, of those 555 patients, 56% had the UK variant, and the majority had COVID-19 worrying variant, like the South African, Brazilian or Californian variants.
Currently, in the United States, about 42% of the population is fully vaccinated against COVID-19, according to the CDC. In Miami-Dade County, that number is 46.8% and in Broward County, 41.8% of residents are fully immunized. Doctors at the University of Miami are hoping that over the next few weeks more South Florida residents will be vaccinated. According to Abbo, this will help prevent the growth of COVID-19 variants and more breakthrough cases.
âWe need to remain vigilant with the emergence of new variants and new cases from South America,â said Abbo, who is also chief infection prevention and microbial management at Jackson Health System. âAnd we must continue to protect ourselves and those around us by continuing to wear masks around unvaccinated people and vulnerable patients until the pandemic is globally under control. “
In her presentation, Abbo described the breakthrough infections she observed in a small number of patients and hospital workers. While these aren’t usually fatal cases, Abbo still wants to investigate why the COVID-19 vaccines haven’t provided protection to these people.
âClinicians need to be aware that breakthrough infections are a possibility, and we’re trying to figure it out. . , why do we see this lack of clinical response in [some] patients, âshe says. “We know the vaccine protects against mortality, but it’s something we’re seeing a little more frequently than three months ago.”
Anjan went on to describe the groundbreaking cases they saw among 27 patients in Miami. She said the majority of these patients were immunocompromised and had recently had an organ transplant, and that they often suffered from other health problems, such as high blood pressure or diabetes. Additionally, most of the breakthrough patients were Hispanic and between the ages of 58 and 89. In addition, half of the patients mentioned being exposed to an unvaccinated family member with COVID-19, Anjan said. Once diagnosed with COVID-19, most of the 27 patients received treatment with monoclonal antibodies, along with high-dose intravenous steroids, and returned home.
However, given that researchers believe COVID-19 variants may be behind these groundbreaking cases, Andrews – who is leading an academic effort to track COVID-19 variants – also presented on the video conference.
Andrews convened a research team in January to develop tests for common COVID-19 variants – such as the UK variant – and to sequence some of the positive test samples to find out which variants are circulating in the student and patient population of the ‘University. Since Andrews is also the vice chief of pathology for Jackson Health System, he was also able to include samples from patients at their three hospitals, providing a more comprehensive overview of COVID-19 in Miami-Dade County.
At the start of their sampling, Andrews said the team noticed a big increase in the British variant. But he quickly began to see many other variants emerging, including strains from Saudi Arabia, Aruba, Nigeria, and other diverse geographic origins, as well as the California, New York, and Brazilian variants. This was not surprising given the diverse population of Miami and its reputation as a gateway to the Americas.
âToday, although [the UK variant] still remains a significant percentage and the predominant variant, with around 40 percent of the samples, we have seen the emergence of other variants. And about 80 to 90 percent of our samples are a worrisome variant or an interesting variant, âhe said.
In their latest sequencing, Andrews noted that 27% of his samples contained the Brazilian variant, 18% had the New York variant, and 8% of the samples represented the California variant, as well as two samples containing an interesting emerging variant from Colombia.
Fortunately, however, Andrews said the drop in COVID-19 positive samples indicates the effectiveness of the vaccines. “The good news is that because the cases are on the decline, despite a significant expansion of variants, this probably indicates that the vaccines used protect against the dominant circulating variants,” he said.