Photo Essay: Partnering to Study a COVID-19 Variant that Threatened Healthcare Workers in Brazil

Arial photo of Manaus, Brazil.

More than two million people live in Manaus, the capital of the Brazilian state Amazonas. This is where in early 2021 a new COVID-19 variant named “Gamma” was first detected. More people died of COVID-19 in this North Brazilian state in the first two months of 2021 than in all of 2020.

Photo of ambulance parked at hospital in Manaus, Brazil, during COVID-19 pandemic.

As Gamma spread throughout Amazonas, healthcare systems became overwhelmed. In a couple of weeks, between January 1 and January 15, 2021, the number of hospitalizations in Manaus increased from 1,900 to 3,900. Healthcare personnel played a critical role saving lives and limiting the spread of COVID-19. However, they were also at risk of disease. It was urgent to learn how fast Gamma spreading and how severe it was.

Photo of ambulance bay at Hospital e Pronto-Socorro 28 Augosto Hospital in Manaus, Brazil, during COVID-19 pandemic.

When COVID-19 vaccines arrived in Brazil, healthcare personnel were one of the groups given highest priority for vaccination by the Brazil Ministry of Health. In early 2021, from January 19 to March 31, a vaccination campaign resulted in 51,000 first doses and 43,000 second doses administered to healthcare personnel in the state of Amazonas by March 31, 2021.

Photo of masked public health workers from Brazil and U.S. CDC working on the COVID-19 response in Brazil.

In 2020, U.S. CDC expanded its presence in Brazil by opening the South America Regional office, building on nearly two decades of collaboration. In early 2021, Brazil invited CDC to partner in its response to the uptick of COVID-19. In March, CDC sent a team of experts to Manaus to collaborate with Brazilian counterparts. U.S. CDC’s infectious disease expert Dr. Fernanda Lessa (on left) worked and trained staff of the Amazonas Health Surveillance Foundation to investigate the COVID-19 outbreak caused by Gamma. Together, the partners developed strategies to protect healthcare personnel and patients.

Photo of exterior of Hospital e Pronto Socorro Dr Aristóteles Platão Bezerra de Araújo in Manaus, Brazil

To understand how the new variant was spreading among healthcare personnel, including those who were vaccinated, Brazil and CDC counterparts decided to conduct a study. One of the first steps was to partner with two public hospitals in Manaus, Hospital e Pronto-Socorro 28 Augosto and Hospital e Pronto Socorro Dr Aristóteles Platão Bezerra de Araújo. Personnel from these hospitals were asked to participate as coordinators or participants.

Photo of hospital workers, wearing masks, who investigated spread of Gamma Variant among healthcare

CDC trained hospital personnel who were going to support the study as coordinators and team members. They were in charge of collecting consistent samples for the study. They interviewed study participants, and asked about COVID-19 symptoms and healthcare activities. One team led by nurse Ariana Mendes (in center of photo), worked at Platão Araújo Hospital. Mendes shared that personally and professionally it was enriching to be involved in the study. Her team, in the picture with her, was proud to engage in this important work.


Staff from both hospitals were asked to participate in the study. Over 380 healthcare personnel volunteered to be monitored at each hospital. They answered questions and had their noses swabbed. Blood samples were taken during the first and fourth week of follow-up. These activities helped determine if hospital staff had COVID-19 without having symptoms, to monitor the spread of the disease among staff, if vaccinated staff got infected with the Gamma variant, and to find out how their immune system responded to the vaccine.


The project coordinator at Hospital 28 de Agosto was nurse Cássia Lima. She coordinated a team that collected the material to be sent to the State Central Laboratory – Lacen for PCR testing and to the Fiocruz laboratory for serology. Lima said that the integration of the local staff with CDC was ongoing and included daily coordination and communication with CDC headquarters.

Arial photo of hospital in Manaus, Brazil.

Only a small portion of vaccinated healthcare personnel at Hospital Platão Araújo (seen here) and Hospital de 28 Agosto tested positive for COVID-19 within 5 months after getting their second dose of COVID-19 vaccine. None of the infected staff were hospitalized and those vaccinated had fewer symptoms and cleared the virus more quickly than those who were unvaccinated.

U.S. CDC supported Brazil with expert assistance to expand response capacity for COVID-19 and to conduct research about Gamma.