The winter COVID-19 wave may be smaller this year; the flu virus has mutated and vaccines are expected to not be as effective; and experts are keeping a close eye on possible human-to-human transmission in avian flu, Johns Hopkins public health experts said.
Kari Debbink, PhD, assistant teaching professor, and Andrew Pekosz, PhD, professor, both in the Baltimore-based Johns Hopkins Bloomberg School of Public Health, held a media advisory call Oct. 2 to discuss trends in infectious diseases this year.
Here are the key trends to know:
COVID-19: This summer saw a larger surge of cases than expected; however, cases have since plateaued and are going down. Experts said that because of the large summer surge, there is a possibility the winter wave will be smaller, as those infected over the summer will have immunity through January. The CDC said it is tracking a new strain, XEC, which has gained traction in the last few weeks.
RSV: A surge of respiratory syncytial virus is expected to appear soon, primarily in children and adults over 65.
H3N2 flu: The H3N2 flu virus has circulated and mutated in the Southern Hemisphere so that the vaccine is not as effective as in previous years. The CDC found this year's vaccine had a 34.5% effectivenss against hospitalization, compared to 51.9% effectiveness of last year's vaccine. The change doesn't affect vaccine recommendations, but public health officials are keeping a close eye on activity.
Mpox: There are no new mpox variants in the U.S.; however, mpox has made the news for its historic spread around the globe. WHO declared a public health emergency of international concern, but the U.S. has the appropriate infrastructure to handle any cases that might arise in the nation.
H5N1 avian flu: Right now, H5N1 avian influenza is at the top of the list of viruses that public health officials are concerned about in terms of pandemic potential. There have been about 14 human infections of H5N1 so far. Preparations have already been made to select vaccine strains that match H5N1 and generate a stock that can be scaled if needed. However, a full distribution pathway is not in place because the risk to the general public remains low. There is an emphasis on trying to control the H5N1 outbreak as flu season approaches in order to prevent the virus from emerging in the human population.
Recently, a healthcare worker who treated an individual with H5N1 showed coughing symptoms shortly after caring for the patient. It is not yet confirmed if this healthcare worker was exposed to H5N1, and experts are waiting 28 days before conducting a blood test that can determine if they were actually infected with H5N1. If so, this would be the first case of human-to-human transmission. This case highlights the need to improve surveillance and testing capabilities to detect the first evidence of transmission among humans.
Parvovirus: In the past year, there has been a significant increase in parvovirus cases. While most recover, it's important that high-risk groups are aware of this trend. This includes pregnant individuals and people with blood disorders. High-risk groups should take extra precautions and avoid contact with children showing respiratory virus symptoms.