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About the series
Monkeypox has been in the news lately, with almost 400 cases in Europe, North America and Asia. Historically, monkeypox is rare, with most of those cases in Central and West Africa. The first outbreak in the Western Hemisphere was caused by diseased prairie dogs in the U.S. in 2003.
Monkeypox was first identified in research primates in 1959, although the typical hosts for this disease are rodents, with monkeys or humans as incidental hosts. Monkeypox is in the orthopox family of viruses (like smallpox), and not related at all to chickenpox (which is a herpes virus).
Monkeypox is often asymptomatic. For individuals with symptoms, they start five to 21 days after exposure to the virus. Infected individuals will have a “prodrome” or early symptoms that typically include a fever, feeling tired and achy, and enlarged lymph nodes. Symptoms will progress to a blistery rash, which sometimes includes the palms. The blisters become filled with pus and eventually crust over. Those with monkeypox are contagious until all of their lesions have crusted over, which is often another three weeks or longer.
Monkeypox is transmitted through animal bites or scratches, or direct contact with skin lesions. It can also be transmitted through large droplet respiratory secretions, although it is dramatically less transmissible than COVID-19. Most of the recent cases of monkeypox have been diagnosed in men who have sex with men – although transmission clearly doesn’t require sexual intimacy, just close contact.
Smallpox vaccination is highly effective at preventing transmission, but smallpox vaccination was stopped in the U.S. in 1971, so most Americans do not have this immunity. Many governments continue to have stockpiles of smallpox vaccination, which can be released if necessary. Vaccination can prevent infection even if administered shortly after exposure. Two antiviral drugs apparently reduce symptom duration, although all studies have been quite small.
Implications for employers
Both reported cases and hospitalizations are up about a third over the last two weeks. The U.S. passed the tragic milestone of a million deaths from COVID-19 since I wrote my last post. While there are few hospitals with critical capacity shortage, about a quarter of counties in the country have moderate or high rates of community transmission. A few school districts (including Philadelphia) have returned to mask mandates, and White House COVID-19 coordinator, Ashish Jha, M.D. M.P.H., recommends that those in communities with high rates of transmission wear masks when indoors.
A large Veterans Administration study of electronic medical records shows that those who had COVID-19 after vaccination (breakthrough infections) were dramatically less likely to die and somewhat less likely to have post-COVID-19 symptoms compared to those who were infected without vaccination. The study showed impressive (statistically significant) effects, although some press headlines suggested that vaccination didn’t prevent many symptoms of long COVID. The study showed that those who were vaccinated were 34% less likely to die and 15% less likely to have at least one post-COVID-19 symptom.
Over the last two weeks, the CDC has recommended booster COVID-19 vaccinations for children ages five to 12 at least five months after their second dose and upgraded its advice for a second booster for those over age 50 to a “recommendation.” We expect the Food and Drug Administration and the CDC to have public meetings on Moderna and Pfizer vaccines for children ages six months to five years of age in mid-June.
The data are currently about a week old, and there is only partial or no coverage in some states. The CDC recently contracted with Biobot to add an additional 500 sampling sites across the country over the next year.
The antiviral Paxlovid was shown in clinical trials to decrease the likelihood of COVID-19-related hospitalization or death by almost 90%, but those clinical trials were limited to unvaccinated people at high risk of complications. As the drug has become more available and is often given to those who are up to date on vaccination when infected, there are more reports of people who recover quickly only to become symptomatic and have positive home tests shortly after finishing the five day course of treatment.
Those who are at higher risk of COVID-19 complications are still recommended to be treated with Paxlovid, which should be given within five days of onset of symptoms. If symptoms recur, they should assume they are infectious and re-isolate for at least five days. They should not return to the workplace until they are asymptomatic, and many would recommend having two days of negative antigen tests prior to returning to the workplace.
Jeff is an internal medicine physician and has led WTW’s clinical response to COVID-19 and other health-related topics. He has served in leadership roles in provider organizations and a health plan and is an Assistant Professor at Harvard Chan School of Public Health.
