In a recent study published in the journal Drugs, researchers reviewed preventive and therapeutic measures against monkeypox.
Study: Prevention and treatment of monkeypox. Image credit: Corona Borealis Studio / Shutterstock
Human smallpox virus is a double-stranded (ds) deoxyribonucleic acid (ds) virus that belongs to the genus orthopoxvirus. Monkeypox infection has manifestations similar to those seen in smallpox. According to the Centers for Disease Control and Prevention (CDC), there are currently no specific treatments for monkeypox infections.
Prevention of monkeypox infection
Several studies have shown that previous smallpox vaccination can induce a protective impact against the smallpox virus and also treat the clinical symptoms associated with smallpox. To date, there are a total of three smallpox vaccines, including the approved JYNNEOSTM and ACAM2000 and the Aventis Pasteur Smallpox Vaccine (APSV).
JYNNEOSTM, developed from the modified Ankara-Bavarian Nordic vaccine (MVA-BN strain), is a live viral vaccine that is an attenuated, non-replicating orthopoxvirus. This vaccine is used as a preventive treatment for smallpox and smallpox among adults 18 years of age or older who are considered at risk for smallpox and smallpox infections. In addition, previous data have revealed that smallpox immunization with vaccine virus was almost 85% effective against monkeypox virus.
ACAM2000 comprises a live vaccine virus and is used for smallpox vaccination for people who have a high risk of getting smallpox infection. The CDC has an emergency access IND protocol that allows the use of ACAM2000 against non-smallpox orthopox virus infections, such as monkeypox during outbreaks of infection.
The Aventis Pasteur smallpox vaccine (APSV) includes a vaccine that was competent for replication that could be used with an emergency use authorization (US) or IND to prevent a smallpox infection when others Authorized vaccines are contraindicated or not available. However, the effectiveness of APSV against monkeypox is not known.
Pre-exposure prophylaxis
The Advisory Committee on Immunization Practices (ACIP) has recommended orthopoxvirus vaccination for selected individuals who are at risk of occupational exposure to the virus. Clinical laboratory staff performing orthopoxvirus diagnostic tests, research laboratory staff, and designated response team members at risk for occupational exposure to the virus are advised to be vaccinated against orthopoxviruses.
Post-exposure prophylaxis
Transmission of monkeypox requires closer interaction for longer with a symptomatic person. Brief interactions, as well as interactions in which appropriate personal protective equipment (PPE) has been used, are not high risk and do not require post-exposure prophylaxis (PEP).
On the other hand, it is advised that the incidences of high degree of exposure to a symptomatic person be monitored and receive a PEP vaccine. An intermediate degree of exposure ensures follow-up and an informed clinical decision that must be made individually to assess whether the benefits associated with PEP outweigh the corresponding risks. In addition, it is advisable to control low or uncertain exposures, but there are no recommendations on PEP.
Treatment of smallpox of the monkey
Supportive care
While most patients with monkeypox recover without the need for medical attention, patients with gastrointestinal symptoms need oral or intravenous rehydration to slow any gastrointestinal fluid loss.
Antiviral treatment
Several antiviral drugs could also be effective in treating monkeypox, as these drugs were approved to control diseases such as smallpox.
Tecovirimat
Tecovirimat is the first approved antiviral used to treat smallpox in adults and pediatric patients and is considered the treatment of choice. Patients with severe disease were treated with dual therapy comprising tecovirimate and brincidofovir. Tecovirimat works by inhibiting the viral envelope protein that is responsible for blocking the final steps involved in viral maturation and subsequent release of the infected cell, leading to inhibition of viral spread within the infected host.
Brincidofovir and Cidofovir
Brincidofovir is an antiviral that has been used to treat smallpox since June 2021 in the US. Orally administered brincidofovir is an analogue of antiviral cidofovir that is administered intravenously. Brincidofovir has been found to have a better safety profile with lower renal toxicity compared to that observed in cidofovir. Both antivirals work by inhibiting viral DNA polymerase. In addition, several studies have shown the effectiveness of brincidofovir against orthopoxvirus infections; however, there is limited research on treatment with brincidofovir for monkeypox.
Vaccine Immunoglobulin (VIG)
VIG, a hyperimmune globulin, is licensed by the Food and Drug Administration (FDA) as a treatment for certain vaccine-related complications. These complications include progressive vaccine, eczema vaccinatum, vaccinia infections among people suffering from skin-related conditions, severe generalized vaccine, and aberrant infections caused by the vaccine virus. While VIG could be a potential treatment approach, there are limited data on the effectiveness of VIG against smallpox and monkeypox.
Conclusion
The results of the study showed that while several individuals infected with monkeypox show mild and self-limiting symptoms even without any medical interference, the prognosis of infection may depend on several factors, such as the state of initial health, previous vaccination status, and concurrent comorbidities. Therefore, the researchers believe that the development of personalized treatments according to the individual risk of experiencing symptoms of severe infection is the most reasonable approach.