Monkeypox (Mpox) requires continued surveillance, vaccines, therapeutics and mitigating strategies

The widespread outbreak of the monkeypox virus (MPXV) recognized in 2022 poses new challenges for public healthcare systems worldwide. With more than 86,000 people infected, there is concern that MPXV may become endemic outside of its original geographical area leading to repeated human spillover infections or continue to be spread person-to-person. Fortunately, classical public health measures (e.g., isolation, contact tracing and quarantine) and vaccination have blunted the spread of the virus, but cases are continuing to be reported in 28 countries in March 2023. We describe here the vaccines and drugs available for the prevention and treatment of MPXV infections. However, although their efficacy against monkeypox (mpox) has been established in animal models, little is known about their efficacy in the current outbreak setting. The continuing opportunity for transmission raises concerns about the potential for evolution of the virus and for expansion beyond the current risk groups. The priorities for action are clear: 1) more data on the efficacy of vaccines and drugs in infected humans must be gathered; 2) global collaborations are necessary to ensure that government authorities work with the private sector in developed and low and middle income countries (LMICs) to provide the availability of treatments and vaccines, especially in historically endemic/enzootic areas; 3) diagnostic and surveillance capacity must be increased to identify areas and populations where the virus is present and may seed resurgence; 4) those at high risk of severe outcomes (e.g., immunocompromised, untreated HIV, pregnant women, and inflammatory skin conditions) must be informed of the risk of infection and be protected from community transmission of MPXV; 5) engagement with the hardest hit communities in a non-stigmatizing way is needed to increase the understanding and acceptance of public health measures; and 6) repositories of monkeypox clinical samples, including blood, fluids, tissues and lesion material must be established for researchers. This MPXV outbreak is a warning that pandemic preparedness plans need additional coordination and resources. We must prepare for continuing transmission, resurgence, and repeated spillovers of MPXV.

Strategies for Vaccine Prioritization and Mass Dispensing

We propose a system that helps decision makers during a pandemic find, in real time, the mass vaccination strategies that best utilize limited medical resources to achieve fast containments and population protection. Our general-purpose framework integrates into a single computational platform a multi-purpose compartmental disease propagation model, a human behavior network, a resource logistics model, and a stochastic queueing model for vaccination operations. We apply the modeling framework to the current COVID-19 pandemic and derive an optimal trigger for switching from a prioritized vaccination strategy to a non-prioritized strategy so as to minimize the overall attack rate and mortality rate. When vaccine supply is limited, such a mixed vaccination strategy is broadly effective. Our analysis suggests that delays in vaccine supply and inefficiencies in vaccination delivery can substantially impede the containment effort. Employing an optimal mixed strategy can significantly reduce the attack and mortality rates. The more infectious the virus, the earlier it helps to open the vaccine to the public. As vaccine efficacy decreases, the attack and mortality rates rapidly increase by multiples; this highlights the importance of early vaccination to reduce spreading as quickly as possible to lower the chances for further mutations to evolve and to reduce the excessive healthcare burden. To maximize the protective effect of available vaccines, of equal importance are determining the optimal mixed strategy and implementing effective on-the-ground dispensing. The optimal mixed strategy is quite robust against variations in model parameters and can be implemented readily in practice. Studies with our holistic modeling framework strongly support the urgent need for early vaccination in combating the COVID-19 pandemic. Our framework permits rapid custom modeling in practice. Additionally, it is generalizable for different types of infectious disease outbreaks, whereby a user may determine for a given type the effects of different interventions including the optimal switch trigger.

Confronting the threat of bioterrorism: realities, challenges, and defensive strategies

Global terrorism is a rapidly growing threat to world security, and increases the risk of bioterrorism. In this Review, we discuss the potential threat of bioterrorism, agents that could be exploited, and recent developments in technologies and policy for detecting and controlling epidemics that have been initiated intentionally. The local and international response to infectious disease epidemics, such as the severe acute respiratory syndrome and west African Ebola virus epidemic, revealed serious shortcomings which bioterrorists might exploit when intentionally initiating an epidemic. Development of new vaccines and antimicrobial therapies remains a priority, including the need to expedite clinical trials using new methodologies. Better means to protect health-care workers operating in dangerous environments are also needed, particularly in areas with poor infrastructure. New and improved approaches should be developed for surveillance, early detection, response, effective isolation of patients, control of the movement of potentially infected people, and risk communication. Access to dangerous pathogens should be appropriately regulated, without reducing progress in the development of countermeasures. We conclude that preparedness for intentional outbreaks has the important added value of strengthening preparedness for natural epidemics, and vice versa.

Transmission of rabies virus from an organ donor to four transplant recipients

BACKGROUND

In 2004, four recipients of kidneys, a liver, and an arterial segment from a common organ donor died of encephalitis of an unknown cause.

METHODS

We reviewed the medical records of the organ donor and the recipients. Blood, cerebrospinal fluid, and tissues from the recipients were tested with a variety of assays and pathological stains for numerous causes of encephalitis. Samples from the recipients were also inoculated into mice.

RESULTS

The organ donor had been healthy before having a subarachnoid hemorrhage that led to his death. Encephalitis developed in all four recipients within 30 days after transplantation and was accompanied by rapid neurologic deterioration characterized by agitated delirium, seizures, respiratory failure, and coma. They died an average of 13 days after the onset of neurologic symptoms. Mice inoculated with samples from the affected patients became ill seven to eight days later, and electron microscopy of central nervous system (CNS) tissue demonstrated rhabdovirus particles. Rabies-specific immunohistochemical and direct fluorescence antibody staining demonstrated rabies virus in multiple tissues from all recipients. Cytoplasmic inclusions consistent with Negri bodies were seen in CNS tissue from all recipients. Antibodies against rabies virus were present in three of the four recipients and the donor. The donor had told others of being bitten by a bat.

CONCLUSIONS

This report documenting the transmission of rabies virus from an organ donor to multiple recipients underscores the challenges of preventing and detecting transmission of unusual pathogens through transplantation.

Hemorrhagic fever with renal syndrome: a study of sequelae following nephropathia epidemica

Sequelae following Nephropathia epidemica (NE) were investigated in 792 individuals living in an endemic area of Sweden. Volunteers were tested for presence of Puumala (PUU) virus specific IgG antibodies in serum, as well as several parameters linked with renal dysfunction and cardiovascular disease (systolic and diastolic blood pressure, ECG, BMI, total cholesterol and serum creatinine). No differences were seen in any of the variables tested between PUU virus antibody positive (n = 110) and negative individuals (n = 682). In addition, the blood pressure was measured in 62 serologically confirmed patients diagnosed with clinical NE 2-6 years previously. One patient with moderate hypertension was found.

A study of nephropathia epidemica among military personnel in sweden

The incidence of nephropathia epidemica (NE), caused by Puumala virus, among military troops operating in an endemic area of Sweden was investigated. A total of 705 soldiers (age 18-25) involved in field training in three different endemic counties were bled twice within a 6-month interval. Three individuals seroconverted when tested for Puumala virus antibodies by IgG ELISA. Symptoms typical of NE were not recorded in any of the patients. However, mild febrile episodes were recorded in 2 of the 3 individuals. One serologically confirmed soldier with typical NE symptoms was found in another group of 12,000 troops. This soldier fell ill 3 weeks after a 7-day-long field exercise. The present study indicates that military populations are at considerably greater risk of contracting NE when compared to the entire population residing in the same area.

Haemorrhagic fever with renal syndrome: evaluation of ELISA for detection of Puumala-virus-specific IgG and IgM

IgM and IgG ELISA to Puumala virus were evaluated using sera from patients with haemorrhagic fever with renal syndrome (HFRS) from different geographical regions: Sweden, Denmark, Norway, Belgium and the European USSR. IgM ELISA proved useful in the diagnosis of HFRS in patients from all the regions mentioned above. Specific IgM could be detected as early as day 1 post onset of disease, and patients remained IgM-positive for several months. Specific IgG ELISA antibodies were also frequently detected in acute sera, and acute-convalescent serum pairs often failed to show a significant titre rise or increase in optical density (OD) values. This limits the use of IgG ELISA in patient diagnosis. Sera collected 2 years after infection revealed higher IgG ELISA OD readings than convalescent sera, and very high values were still detectable 10 to 20 years postinfection. IgG ELISA is therefore useful for the testing of immunity and in seroepidemiological studies. Acute and convalescent sera from HFRS patients in Korea and the Asian USSR showed no or only very weak reactivity in the Puumala virus IgG and IgM ELISA. These results are consistent with the "one-way" crossing described earlier.

Demographic consequences of artificial selection at the LAP locus in voles (Microtus townsendii)

A number of studies on small mammals have shown that changes in the frequency of alleles at polymorphic loci are correlated with population fluctuations. To determine whether the genetic composition of a population affected its density changes, we altered gene frequencies in two field populations of the vole Microtus townsendii. The fast allele, LAPF, was present in a control population at a frequency of about 35% from July 1971 to July 1973. By removing homozygous LAPS/LAPS voles from one experimental population we maintained an LAPF frequency of about 75%. Removal of LAPF/LAPF homozygotes from a second population resulted in an LAPF frequency of about 25%. We monitored demographic variables of the populations while the selection was being applied. The populations went through increasing and peak phases and then declined sharply during the spring of 1973. Different genotypes had an advantage in survival and reproduction during different phases of population density on the control area, and the selection that maintained the polymorphism on the control area could be correlated with population density. The altered allelic frequencies on the experimental areas did not produce any consistent effects on demography.