The US Centers for Disease Control and Prevention (CDC) today issued a health alert to clinicians about a confirmed measles case in an individual who attended a religious gathering in Kentucky involving about 20,000 people, including participants from other US states and other countries.

The patient was at the event at Asbury College on Feb 17 and 18 while he or she was infectious, and the CDC said an undetermined number of people may have been exposed. The individual diagnosed as having measles had a history of recent international travel and was unvaccinated.

Measles is highly contagious, with an incubation period of about 10 days with rash onset occurring at about 14 days.

The CDC warned that measles vaccination rates have declined during the COVID-19 pandemic and that measles outbreaks are occurring in all world regions, with large outbreaks involving 20 or more cases reported in Europe, Africa, the Middle East, and Southeast Asia. Cases in the United States jumped from 49 cases in 2021 to 121 cases in 2022, all in children who weren't fully vaccinated. The numbers include outbreaks in Minnesota and Ohio.

The CDC urged clinicians to consider measles in patients with compatible symptoms in people who attended the event in Kentucky during the exposure dates, as well as in their contacts and those who recently traveled abroad. It also encouraged health providers to offer to the measles, mumps, and rubella (MMR) vaccine to people who aren't fully vaccinated.

Although bacterial co-infections were identified infrequently in hospitalized US COVID-19 patients, they were associated with a more than two-fold higher risk of death, US researchers reported yesterday in Influenza and Other Respiratory Viruses.

Using data from the Coronavirus Disease 2019-Associated Hospitalization Surveillance Network (COVID-Net), which includes more than 250 acute care hospitals in 14 states, a team led by the Centers for Disease Control and Prevention (CDC) investigated the incidence of bacterial and viral co-infections among hospitalized adults with confirmed SARS-CoV-2 infections from March 2020 to April 2022. They then compared demographic and clinical features among those with and without bacterial co-infections.

Among a representative sample 36,490 hospitalized adults with COVID-19, 53.3% had bacterial cultures taken within 7 days of admission, and 6.0% had a clinically relevant bacterial pathogen in sputum, blood, deep respiratory tissue, or another sterile site.

Understanding risk factors for bacterial infections and associated outcomes can help guide clinicians in providing optimal care.

The most frequently isolated organism from all sites was Staphylococcus aureus, followed by gram-negative rods, including Pseudomonas aeruginosa, Klebsiella pneumoniae, and Escherichia coli. In-hospital death occurred in 31.7% of those with bacterial co-infections, compared with 13.2% of those without bacterial co-infections in bivariate analysis.

After controlling for demographic factors, underlying medical conditions, and time period, adults with COVID-19 who had bacterial co-infections within 7 days of admission had a relative risk [RR] of 2.28 (95% confidence interval [CI], 1.87 to 2.79) for death compared with those who had negative bacterial cultures. Those with a clinically relevant pathogen identified were also associated with an increased need for intensive care (RR, 2.11; 95% CI, 1.95 to 2.23) and mechanical ventilation (RR, 3.04; 95% CI, 2.74 to 3.37).

"As SARS-CoV-2 continues to circulate and individuals continue to be hospitalized for COVID-19, understanding risk factors for bacterial infections and associated outcomes can help guide clinicians in providing optimal care," the study authors conclude.

The average time for symptom onset between successive mpox cases (serial interval) is 8.5 days, and the average time between infection and symptom onset (incubation period) is 5.6 days, estimates a study published yesterday in Emerging Infectious Diseases.

From May to August 2022, researchers from the Centers for Disease Control and Prevention (CDC) analyzed data from 12 US health departments to estimate average serial interval based on 57 mpox case pairs and incubation period based on 35 case pairs. Since the global mpox outbreak began in May 2022, 86,231 infections and 105 deaths have been reported in 110 countries.

Mpox symptoms typically begin within 3 weeks of exposure and may include fever, headache, chills, swollen lymph nodes, and exhaustion, followed by a rash 1 to 4 days later, the authors noted. In the current outbreak, transmission has occurred largely through close physical contact among men who have sex with men. Spread is possible from symptom onset until all scabs have dropped off and fully healed.

Shorter serial interval for rash onset

The estimated serial interval was 8.5 (95% credible interval [CI], 7.3 to 9.9) days for symptom onset and 7.0 (95% CI, 5.8 to 8.4) days for rash onset, and the estimated incubation period was 5.6 (95% CI, 4.3 to 7.8) days for symptom onset and 7.5 (95% CI, 6.0 to 9.8) days for rash onset.

The serial interval for symptom onset ranged from 2 to 25 days, which the researchers said could be partially attributable to the nature and intensity of the physical contact.

The authors said that their serial interval estimate is similar to that of one from the United Kingdom (9.8 days) but shorter than the 12.5 days estimated by Italian researchers in May and June 2022.

"Serial interval changes can be very rapid," they wrote. "The serial interval correlates with human behavior and can decrease with increasing awareness among men who have sex with men or interventions, a pattern similar to that observed among the general population during the COVID-19 pandemic."

The Centers for Disease Control and Prevention (CDC) yesterday issued a Health Alert Network (HAN) Health Advisory to clinicians and public health officials warning that US travelers could be affected by a growing chikungunya outbreak in Paraguay.

Since the chikungunya outbreak began in October 2022, the Ministry of Health in Paraguay has reported 71,748 suspected cases of the mosquito-borne alphavirus, with 29,362 of those cases being probable or confirmed. Most cases have been reported in the capital district of Asuncion and the neighboring Central department. Further increases in case counts are expected.

Paraguay is among several countries in the region of the Americas seeing an increase in chikungunya activity. In February, the Pan American Health Organization reported that cases in the region were up sharply in 2022, with 271,000 illnesses reported, up from 137,000 in 2021.

The virus is transmitted primarily by infected Aedes aegypti and Aedes albopictus mosquitoes. The incubation period in infected people is typically 3 to 7 days, and the most common symptoms are acute onset of fever and joint pain. No specific antivirals or vaccines are available.

Ruling out dengue

The CDC says travelers returning from Paraguay with signs and symptoms consistent with chikungunya infection should be tested and evaluated. The health advisory also notes that clinicians should rule out infection with dengue virus, which is also transmitted by mosquitoes, has similar symptoms, and circulates in Paraguay and surrounding countries.

The health advisory advises state and local health departments to report confirmed chikungunya cases to the CDC.