Effect of Serial Passage on the Pathogenicity and Immunogenicity of Vaccinia Virus LC16m8 Strain

Molecular Virology of Orthopoxviruses with Special Reference to Monkeypox Virus

Poxviruses are large (200-450 nm) and enveloped viruses carrying double-stranded DNA genome with an epidermal cell-specific adaptation. The genus Orthopoxvirus within Poxviridae family constitutes several medically and veterinary important viruses including variola (smallpox), vaccinia, monkeypox virus (MPXV), and cowpox. The monkeypox disease (mpox) has recently emerged as a public health emergency caused by MPXV. An increasing number of human cases of MPXV have been documented in non-endemic nations without any known history of contact with animals brought in from endemic and enzootic regions, nor have they involved travel to an area where the virus was typically prevalent. Here, we review the MPXV replication, virus pathobiology, mechanism of viral infection transmission, virus evasion the host innate immunity and antiviral therapies against Mpox. Moreover, preventive measures including vaccination were discussed and concluded that cross-protection against MPXV may be possible using antibodies that are directed against an Orthopoxvirus. Despite the lack of a specialised antiviral medication, several compounds such as Cidofovir and Ribavirin warrant consideration against mpox.

A systematic review to identify novel clinical characteristics of monkeypox virus infection and therapeutic and preventive strategies to combat the virus

Since May 2022, there has been a global increase in the number of Mpox virus (MPXV) cases in countries that were previously considered non-endemic. In July 2022, the World Health Organization (WHO) declared this outbreak a public health emergency of international concern. The objective of this systematic review is to examine the novel clinical features of Mpox and to assess the available treatment options for managing the disease in patients who are afflicted with it. We conducted a systematic search in several databases, including PubMed, Google Scholar, Cochrane Library, and the grey literature, from May 2022 to February 2023. We identified 21 eligible studies, which included 18,275 Mpox cases, for final qualitative analysis. The majority of cases were reported in men who have sex with men (MSM) and immunocompromised individuals with HIV (36.1%). The median incubation period was 7 days (IQR: 3-21). The novel clinical manifestations include severe skin lesions on the palms, oral and anogenital regions, as well as proctitis, penile edema, tonsillitis, ocular disease, myalgia, lethargy, and sore throat, without any preceding prodromal symptoms or systemic illness. In addition, fully asymptomatic cases were documented, and various complications, including encephalomyelitis and angina, were noted. Clinicians must be familiar with these novel clinical characteristics, as they can aid in testing and tracing such patients, as well as asymptomatic high-risk populations such as heterosexuals and MSM. In addition to supportive care, currently, there are several effective prophylactic and treatment strategies available to combat Mpox, including the vaccines ACAM2000 and MVA-BN7, as well as the immunoglobulin VIGIV and the antivirals tecovirimat, brincidofovir, and cidofovir against severe Mpox infection.

Monkeypox: Treatment, Vaccination, and Prevention

In regions where the disease is endemic, Monkeypox (MPV) transmission related to healthcare has been seen on numerous occasions. This disease has episodes of occurrence in certain regions around the globe, such as in the Democratic Republic of Congo's (DRC) Tshuapa region. Here, the disease was found with a prevalence of 0.35 per 1000, as per data collected by the Centers for Disease Control and Prevention (CDC) of the United States (US). Data also shows approximately 100 confirmed cases of MPV for every infection among Healthcare Workers (HCWs). These findings and scientific research on burns, superficial wounds, herpes, eczema vaccine, and other conditions indicate that MPV sufferers might get an advantage from medical care to lessen the effects of weakened skin and mucosa. This should involve guarding delicate anatomical areas like the eyes and genitalia, maintaining enough hydration and nourishment, and preventing and treating consequences like secondary bacterial diseases. In the DRC, this disease was first recognized in 1970. Since then, it has spread to numerous nations around the globe and gained substantial epidemiological significance. The most recent epidemic has taken place in 2022 worldwide. The viruses that cause MPV and cowpox are currently regarded as emerging. Because of the rise in international travel, the popularity of exotic pets, and the decline in smallpox vaccination rates, they pose a significant danger of spreading. Although it is believed that this viral illness will eventually go away on its own, the possibility of the pandemic raises several serious problems for the general public's health. In addition to providing a broad overview of the Monkeypox Virus (MPXV), this study will detail the epidemiology, clinical hallmarks, assessment, and treatment of MPV sufferers.

A replication-competent smallpox vaccine LC16m8Δ-based COVID-19 vaccine

Viral vectors are a potent vaccine platform for inducing humoral and T-cell immune responses. Among the various viral vectors, replication-competent ones are less commonly used for coronavirus disease 2019 (COVID-19) vaccine development compared with replication-deficient ones. Here, we show the availability of a smallpox vaccine LC16m8Δ (m8Δ) as a replication-competent viral vector for a COVID-19 vaccine. M8Δ is a genetically stable variant of the licensed and highly effective Japanese smallpox vaccine LC16m8. Here, we generated two m8Δ recombinants: one harbouring a gene cassette encoding the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) spike (S) glycoprotein, named m8Δ-SARS2(P7.5-S)-HA; and one encoding the S protein with a highly polybasic motif at the S1/S2 cleavage site, named m8Δ-SARS2(P7.5-S_HN)-HA. M8Δ-SARS2(P7.5-S)-HA induced S-specific antibodies in mice that persisted for at least six weeks after a homologous boost immunization. All eight analysed serum samples displayed neutralizing activity against an S-pseudotyped virus at a level similar to that of serum samples from patients with COVID-19, and more than half (5/8) also had neutralizing activity against the Delta/B.1.617.2 variant of concern. Importantly, most serum samples also neutralized the infectious SARS-CoV-2 Wuhan and Delta/B.1.617.2 strains. In contrast, immunization with m8Δ-SARS2(P7.5-S_HN)-HA elicited significantly lower antibody titres, and the induced antibodies had less neutralizing activity. Regarding T-cell immunity, both m8Δ recombinants elicited S-specific multifunctional CD8⁺ and CD4⁺ T-cell responses even after just a primary immunization. Thus, m8Δ provides an alternative method for developing a novel COVID-19 vaccine.

Monkeypox: A New Threat?

The global vaccination programme against smallpox led to its successful eradication and averted millions of deaths. Monkeypox virus (MPXV) is a close relative of the Variola (smallpox) virus. Due to antigenic similarity, smallpox vaccines cross-protect against MPXV. However, over 70% of people living today were never vaccinated against smallpox. Symptoms of monkeypox (MPX) include fever, head- and muscle ache, lymphadenopathy and a characteristic rash that develops into papules, vesicles and pustules which eventually scab over and heal. MPX is less often fatal (case fatality rates range from <1% to up to 11%) than smallpox (up to 30%). MPXV is endemic in sub-Saharan Africa, infecting wild animals and causing zoonotic outbreaks. Exotic animal trade and international travel, combined with the increasing susceptibility of the human population due to halted vaccination, facilitated the spread of MPXV to new areas. The ongoing outbreak, with >10,000 cases in >50 countries between May and July 2022, shows that MPXV can significantly spread between people and may thus become a serious threat to public health with global consequences. Here, we summarize the current knowledge about this re-emerging virus, discuss available strategies to limit its spread and pathogenicity and evaluate its risk to the human population.