CDC issues level 2 travel notice for yellow fever in South America

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aedes
calafellvalo / Flickr cc

Yesterday, the US Centers for Disease Control and Prevention (CDC) issued a level 2 travel notice (practice enhanced precautions) about yellow fever in South America due to a rise in cases and spread to newly affected areas of Bolivia, Colombia, and Peru.

The travel alert urges travelers to the region to get a yellow fever vaccine at least 10 days prior to leaving the United States and says those vaccinated 10 or more years ago may want to consider a booster dose. 

Except for Chile and most of Argentina, all of South America now carries a yellow fever vaccine recommendation, per the CDC’s travel alert site.

First 3 months of 2025 see high activity 

The Pan American Health Organization (PAHO) warned earlier this month of growing yellow fever activity in South America. In the first 3 months of 2025, 131 human cases were confirmed, with 53 deaths. In all of 2024, 61 cases were reported, 30 of which were fatal.

Yellow fever is spread by mosquitoes, and the CDC urges travelers to protect against mosquito bites. 

Though most cases of yellow fever are self-limiting, about 15% of people infected with yellow fever virus develop severe illness that can lead to liver disease, bleeding, shock, organ failure, yellowing skin and eyes, and sometimes death, according to the CDC.


 

Novavax says its COVID vaccine produces fewer, milder reactions than Pfizer version

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Novavax vaccine on pallet
Novavax

Yesterday, Novavax presented early data from a real-world study suggesting that its 2024-25 protein-based COVID-19 vaccine targeting the JN.1 SARS-CoV-2 strain causes fewer and less-severe short-term side effects than the Pfizer/BioNTech mRNA COVID-19 vaccine. 

The Study of Healthcare Workers and First Responders Investigating Effects of Systemic and Local reactogenicity of COVID-19 Vaccine Doses in Utah (SHIELD-Utah) was conducted from September to December 2024 with University of Utah Health (UUH).

The risk of side effects or reactogenicity has been shown to be a major decision factor for those opting to get vaccinated.

Sarang Yoon, DO

A total of 219 healthcare workers received Novavax, and 369 received the Pfizer product. Two and 7 days after immunization, they completed a questionnaire on reactogenicity symptoms and their effects on daily activities. Participants included physicians (20.4% of the total), nurses (19.2%), and medical assistants (11.9%).

The preliminary results were presented at the Congress of the European Society of Clinical Microbiology and Infectious Diseases (ESCMID) 2025 in Vienna.

"The risk of side effects or reactogenicity has been shown to be a major decision factor for those opting to get vaccinated," principal investigator Sarang Yoon, DO, of UUH, said in the Novavax news release.

About 13% fewer local reactions with Novavax

On average, workers who received Novavax had 1.7 systemic symptoms, compared with 2.8 in Pfizer recipients. In total, 43.8% of Pfizer vaccinees reported at least one symptom of moderate or higher grade, compared with 24.2% of Novavax recipients. 

Workers who received Novavax reported 12.5% fewer local reactions than those who received the Pfizer vaccine. Average hours of side effect–related reduced activity were lower in Novavax recipients than in Pfizer vaccinees (0.7 vs 1.4 hours of missed work and 0.8 vs 2.4 hours of lower productivity).

"Our protein-based nanoparticles and Matrix-M adjuvant are the foundation of our COVID-19 vaccine," Ruxandra Draghia-Akli, MD, PhD, executive vice president and head of research and development at Novavax, said in the release. "Our new R&D pipeline is focused on delivering more assets built on this powerful technology platform, including the use of our Matrix M adjuvant, which has been associated with a favorable tolerability profile."

Study suggests US sepsis patients are overtreated

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Sepsis diagnosis
Zerbor / iStock

An analysis of patients treated for sepsis at US hospitals shows that close to 90% were likely overtreated, researchers reported yesterday in Clinical Infectious Diseases.

The study, led by researchers at Brigham and Women's Hospital in Boston and Harvard Medical School, reviewed the medical records of patients treated for suspected sepsis with anti–methicillin-resistant Staphylococcus aureus or antipseudomonal antibiotics in the emergency departments of seven US hospitals from 2019 through 2022. 

In light of concerns that a federally mandated sepsis treatment protocol (SEP-1) that calls for antibiotic administration within 3 hours of sepsis onset might be driving unnecessary broad-spectrum antibiotic use in patients with noninfectious conditions or viral infections, the researchers wanted to assess patients' post hoc likelihood of bacterial infection. They also assessed outcomes, whether narrower-spectrum antibiotics could have been used, and possible antibiotic-associated complications.

1 in 3 mostly likely did not have a bacterial infection

Among 46,245 patients treated for suspected sepsis during the study period, 600 were randomly selected for review. Of those patients, 411 (68.5%) had definite or probable bacterial infections and 189 (31.5%) had possible but less likely or definitely no bacterial infections. Among the patients with definite or probable bacterial infection, 79.1% received overly broad antibiotics. Altogether, 86% of patients may have been overtreated.

Potential antibiotic-associated complications developed in 17.3% of patients within 90 days, most of them involving new infection or colonization with a drug-resistant organism. Mortality was higher for patients with less likely or definitely no bacterial infection versus definite or probable bacterial infections (9.0% vs 4.9%; adjusted odds ratio [aOR], 2.25; 95% confidence interval [CI], 1.70 to 2.98), but antibiotic-associated complication rates were similar (14.8% vs 18.5%; aOR, 0.79; 95% CI, 0.60 to 1.05).

"Our findings support the concern that in the setting of sepsis policies that require rapid administration of broad-spectrum antibiotics, empiric antibiotics for suspected sepsis are often unnecessary or broader than necessary in retrospect," the study authors wrote. "These findings have important implications for antibiotic stewardship efforts in the face of ongoing quality improvement and policy initiatives that seek to speed delivery of broad-spectrum antibiotics for patients with suspected sepsis."

Quick takes: Pandemic Accord draft finalized, H5N1 PCR test, Marburg vaccine progress

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  • A group of World Health Organization (WHO) member states, after 3 years of intensive negotiations, has finalized a draft Pandemic Accord agreement that will be presented at the World Health Assembly (WHA) for a vote in May. The accord’s goal is to strengthen global collaboration to help prevent, prepare for, and respond to future pandemic threats. In 2021 at the height of the COVID-19 pandemic at a special WHA session, WHO member states established the Intergovernmental Negotiating Body (INB) to draft and negotiate a pandemic accord. The group had 13 rounds of formal meetings and many informal sessions to iron out different aspects of the document. In a statement today, WHO Director-General Tedros Adhanom Ghebreyesus, PhD, thanked the team for its tireless work in forging a historic agreement. “In reaching consensus on the Pandemic Agreement, not only did they put in place a generational accord to make the world safer, they have also demonstrated that multilateralism is alive and well, and that in our divided world, nations can still work together to find common ground, and a shared response to shared threats.”
  • HealthTrackRx, a diagnostic testing company based in Denton, Texas, yesterday announced the development of a PCR test for H5N1 avian influenza that was created in a partnership with the US Centers for Disease Control and Prevention (CDC) as part of emergency preparedness. "Our national footprint and next-morning result model uniquely position us to support public health response when timing matters most," Jay Reddy, PhD, the company’s chief scientific officer, said in a press release. "We're working with the CDC to ensure this test is ready to deploy should the need arise.”
  • The Sabin Vaccine Institute today announced the launch of a multisite phase 2 clinical trial of its candidate vaccine against Marburg virus. The first doses were administered to study participants in Melbourne, Florida. The group said the trial builds on phase 2 testing in Kenya and Uganda, with initial findings expected in the months ahead. The vaccine was quickly deployed in response, and as part of a study, to Rwanda’s Marburg virus outbreak in 2024, with more than 1,700 people vaccinated, mainly frontline health workers. Currrently, there are no approved vaccines or treatments for Marburg infection, a viral hemorrhagic fever with a high case-fatality rate that is similar to Ebola virus. Made with a chimp adenovirus type 3 (cAd3) vector, the vaccine is given as a single dose.

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