Genomic diversity of vaccinia virus strain Cantagalo isolated in southeastern Brazil during the early years of the outbreak, 1999-2006

Human mpox: global trends, molecular epidemiology and options for vaccination

The eradication of smallpox and the cessation of vaccination have led to the growth of the susceptible human population to poxviruses. This has led to the increasing detection of zoonotic orthopoxviruses. Among those viruses, monkeypox virus (MPV) is the most commonly detected in Western and Central African regions. Since 2022, MPV is causing local transmission in newly affected countries all over the world. While the virus causing the current outbreak remains part of clade II (historically referred to as West African clade), it has a significant number of mutations as compared to other clade II sequences and is therefore referred to as clade IIb. It remains unclear whether those mutations may have caused a change in the virus phenotype. Vaccine effectiveness data show evidence of a high cross-protection of vaccines designed to prevent smallpox against mpox. These vaccines therefore represent a great opportunity to control human-to-human transmission, provided that their availability has short time-frames and that mistakes from the recent past (vaccine inequity) will not be reiterated.

Mpox Virus in Pregnancy, the Placenta, and Newborn

CONTEXT.—

Before its eradication, the smallpox virus was a significant cause of poor obstetric outcomes, including maternal and fetal morbidity and mortality. The mpox (monkeypox) virus is now the most pathogenic member of the Orthopoxvirus genus infecting humans. The 2022 global mpox outbreak has focused attention on its potential effects during pregnancy.

OBJECTIVE.—

To understand the comparative effects of different poxvirus infections on pregnancy, including mpox virus, variola virus, vaccinia virus, and cowpox virus. The impact on the pregnant individual, fetus, and placenta will be examined, with particular attention to the occurrence of intrauterine vertical transmission and congenital infection.

DATA SOURCES.—

The data are obtained from the authors' cases and from various published sources, including early historical information and contemporary publications.

CONCLUSIONS.—

Smallpox caused maternal and perinatal death, with numerous cases reported of intrauterine transmission. In endemic African countries, mpox has also affected pregnant individuals, with up to a 75% perinatal case fatality rate. Since the start of the 2022 mpox outbreak, increasing numbers of pregnant women have been infected with the virus. A detailed description is given of the congenital mpox syndrome in a stillborn fetus, resulting from maternal-fetal transmission and placental infection, and the potential mechanisms of intrauterine infection are discussed. Other poxviruses, notably vaccinia virus and, in 1 case, cowpox virus, can also cause perinatal infection. Based on the historical evidence of poxvirus infections, mpox remains a threat to the pregnant population, and it can be expected that additional cases will occur in the future.

Genomic Characterization of the Historical Smallpox Vaccine Strain Wyeth Isolated from a 1971 Seed Vial

The Wyeth strain of vaccinia virus (VACV) produced by Wyeth Pharmaceuticals was supposedly used to manufacture the old freeze-dried American smallpox vaccine, Dryvax, until its discontinuation in 2008. Although the genomic sequences of numerous Dryvax clones have been reported, data on VACV-Wyeth genomes are still lacking. Genomic analysis of old VACV strains is relevant to understand the evolutionary relationships of smallpox vaccines, particularly with the recent resumption of smallpox vaccination in certain population groups as an attempt to control the worldwide monkeypox outbreak. Here we analyzed the complete genome sequences of three VACV-Wyeth clonal isolates obtained from a single seed vial donated to the Brazilian eradication program in the 1970s. Wyeth clones show >99.3% similarity to each other and >95.3% similarity with Dryvax clones, mapping together in clade I of the vaccinia group. Although the patterns of SNPs and INDELs comparing Dryvax and Wyeth clones are overall uniform, important differences were detected particularly at the ends of the genome. In addition, we detected recombinant events of clone Wyeth A111 and the Dryvax clone Acam2000, suggesting that other regions of the genomes may have similar patchy patterns of recombination. A small-scale serological survey using VACV-Wyeth as antigen in ELISA assays revealed that 63 of the 65 individuals born before the end of smallpox vaccination in Brazil still have anti-VACV IgG antibodies, demonstrating the usefulness of the VACV-Wyeth strain in future extended serological studies of the Brazilian population.

Twenty Years after Bovine Vaccinia in Brazil: Where We Are and Where Are We Going?

Orthopoxvirus (OPV) infections have been present in human life for hundreds of years. It is known that Variola virus (VARV) killed over 300 million people in the past; however, it had an end thanks to the physician Edward Jenner (who developed the first vaccine in history) and also thanks to a massive vaccination program in the 20th century all over the world. Although the first vaccine was created using the Cowpox virus (CPXV), it turned out later that the Vaccinia virus was the one used during the vaccination program. VACV is the etiological agent of bovine vaccinia (BV), a zoonotic disease that has emerged in Brazil and South America in the last 20 years. BV has a great impact on local dairy economies and is also a burden to public health. In this review, we described the main events related to VACV and BV emergence in Brazil and South America, the increase of related scientific studies, and the issues that science, human and animal medicine are going to face if we do not be on guard to this virus and its disease.