- Possible Occupational Infection of Healthcare Workers with Monkeypox Virus, Brazil
Researchers evaluated epidemiologic and molecular characteristics of monkeypox virus (MPXV) infections sampled from 2 healthcare nurses. Five days after collecting samples from an infected patient, the nurses showed typical MPXV manifestations; quantitative PCR and whole-genome sequencing confirmed MPXV infection, most likely transmitted through contact with fomites.
- Protection of SARS-CoV-2 natural infection against reinfection with the BA.4 or BA.5 Omicron subvariants
Effectiveness of a previous pre-Omicron infection against symptomatic BA.4/BA.5 COVID-19 reinfection was 15.1% (95% CI: -47.1 to 50.9%), and against any BA.4/BA.5 reinfection irrespective of symptoms was 28.3% (95% CI: 11.4 to 41.9%). Effectiveness of a previous Omicron infection against symptomatic BA.4/BA.5 reinfection was 76.1% (95% CI: 54.9 to 87.3%), and against any BA.4/BA.5 reinfection was 79.7% (95% CI: 74.3 to 83.9%).
- Rates of Monkeypox Cases by Vaccination Status
Among 32 U.S. jurisdictions, monkeypox incidence among people who are currently recommended to receive vaccine was higher among unvaccinated people compared with those who had received their first vaccine dose 14 days or more earlier. Several factors likely affect crude case rates by vaccination status. Limitations include the inability to account for possible differences in testing or behaviors between vaccinated and unvaccinated people or possible differences in risk due to patient characteristics such as age or underlying condition status.
- Paxlovid Significantly Reduces COVID-19 Hospitalizations and Deaths
In an unadjusted analysis, patients who are prescribed Paxlovid are about two times less likely to be hospitalized for COVID-19 and about four times less likely to die from COVID-19 than those who might be eligible for Paxlovid but did not receive a Paxlovid prescription. Fully vaccinated patients over age 50 who were treated with Paxlovid are about three times less likely to be hospitalized than those not treated with Paxlovid. Patients aged 40-49 are about two times less likely to be hospitalized when treated with Paxlovid, although results vary depending on vaccination status.
- Nirmatrelvir–Ritonavir and Viral Load Rebound in Covid-19
The incidence of viral load rebound was similar in the nirmatrelvir–ritonavir group and the placebo group. The occurrence of viral load rebound was not retrospectively associated with low nirmatrelvir exposure, recurrence of moderate-to-severe symptoms, or development of resistance to nirmatrelvir. One potential limitation of this analysis is that the clinical trial was conducted during a period of the pandemic when most infections were caused by the B.1.617.2 (delta) variant. However, more recent data indicate that nirmatrelvir–ritonavir is also effective against B.1.1.529 (omicron) variants. Another limitation of this analysis is the focus on identifying potential nirmatrelvir resistance. Viral load as determined by polymerase-chain-reaction assay does not translate directly to the presence of infectious virus and is not perfectly correlated with current or new clinical symptoms. Finally, omicron recurrence has also been observed in untreated patients. In the ACTIV-2/A5401 study, rebounds in viral load and clinical symptoms were relatively common among participants who had not received any antiviral agents. These findings suggest that viral load rebound may be a feature of some SARS-CoV-2 infections and that the natural history of Covid-19 requires continued study.