CDC says mpox vaccine boosters aren’t needed in the US as questions emerge around waning immunity
September 13, 2024
A deadly mpox outbreak, involving the more severe clade Ib strain, is spreading in Africa and globally, prompting the World Health Organization to declare a public health emergency. This follows a 2022 outbreak of clade IIb mpox in the US, which was largely controlled through vaccination. While questions arise about potential booster doses for vulnerable populations in the US, experts like Dr. Ashish Jha currently see no obvious need. The situation highlights the ongoing global health challenges posed by mpox and the importance of vaccination in controlling outbreaks, while also emphasizing the need for continued monitoring and readiness in public health responses.
A resurgence of mpox, particularly a deadly outbreak in Africa, is raising global health concerns and prompting discussions about vaccination strategies. The World Health Organization recently declared the outbreak in the Democratic Republic of Congo a public health emergency of international concern, as the virus spreads to an increasing number of African countries and beyond.
This current outbreak involves clade Ib mpox, a relatively new and more severe strain compared to previous outbreaks. Mpox, formerly known as monkeypox, is characterized by two main genetic clades, I and II. The severity of clade Ib presents new challenges for public health officials and medical professionals.
The situation draws comparisons to the global outbreak in 2022, which was caused by clade IIb mpox and spread primarily through sexual contact. That outbreak affected over 30,000 people in the United States alone and was also declared a public health emergency. However, widespread vaccination with the Jynneos mpox vaccine played a crucial role in slowing transmission, nearly eliminating the virus in the US.
As the new outbreak unfolds, questions are emerging about the potential need for booster doses among vulnerable populations in the United States. Despite these concerns, some experts, including Dr. Ashish Jha, dean of the Brown School of Public Health and former White House Covid-19 response coordinator, currently see no obvious reason for boosters.
Dr. Jha's stance reflects the current understanding that those previously vaccinated likely maintain sufficient protection. However, this position may evolve as more data becomes available about the duration of vaccine efficacy and the characteristics of the clade Ib strain.
The ongoing situation underscores the dynamic nature of infectious disease outbreaks and the importance of robust, adaptable public health responses. It also highlights the critical role of vaccination in controlling the spread of mpox, while emphasizing the need for continued vigilance, research, and global cooperation in addressing emerging health threats.