Tag Archives: smallpox

How Denmark’s 1800s Vaccine Campaign Eradicated Smallpox in Just 7 Years

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Edward Jenner Administering the First Smallpox Vaccination in 1796

Ernest Board/Wellcome Collection/De Agostini via Getty Images

Recent insights into one of history’s most effective vaccination campaigns highlight critical lessons for expediting vaccine adoption today. This successful effort eradicated smallpox in Copenhagen during the early 1800s.

Smallpox, a devastating infectious disease, resulted in a mortality rate of 30% and left survivors with disfigurement and blindness, leading to an estimated 500 million deaths before its global eradication in 1980 through vaccination.

Copenhagen saw one of the earliest local triumphs over smallpox, achieving eradication in 1808 after claiming over 12,000 lives over fifty years.

The world’s first vaccine, developed by British physician Edward Jenner in 1796, quickly gained traction among Denmark’s medical and social elite, sparking “excited attention and anticipation,” as documented by leading physician Henrik Kalissen.

Doctors in Copenhagen swiftly sought smallpox vaccine supplies from Jenner in England. The inaugural recipient was a Danish judge’s child, followed by a bishop’s child. The vaccine proved remarkably effective, preventing transmission even among close contacts of infected individuals, including breastfeeding mothers, according to Calisen’s observations.

In response, the King of Denmark founded a Vaccine Commission in 1801, tasked with broadening the vaccine’s reach and meticulously tracking vaccination rates and smallpox outbreaks.

Researchers from Roskilde University analyzed these records, revealing that by 1810, 90% of Copenhagen’s children had been vaccinated, leading Denmark to rank as the highest in Europe for vaccination rates per capita.

Due to the rapid dissemination of the smallpox vaccine, the disease was eliminated from Copenhagen just seven years after the campaign’s initiation. “We will be free from one of the most destructive diseases known to us,” Calisen expressed in 1809.

Eilersen and his team identified key factors behind the high vaccination rates. Vaccines were offered free of charge to families in need, and many church leaders and school teachers actively promoted and administered the vaccines. The Vaccine Commission commended clergy who traversed the nation to disseminate knowledge about vaccinations, with one priest vaccinating nearly 2,000 children in just one year.

As smallpox cases dwindled, concerns arose about public apathy towards vaccination. To sustain high rates, the committee mandated that vaccination be a prerequisite for a child’s enrollment in church activities as of 1810.

While some resisted vaccinating their children, citing “ignorance and prejudice,” the broader public largely supported vaccination, Calisen noted. He acknowledged initial fears about vaccines but ultimately recognized their tremendous impact on public health and population growth.

Eilersen believes that the collaboration among Danish leaders fostered public trust and encouraged widespread vaccine acceptance. “Unified authorities, including government, medical institutions, and religious leaders, contributed to convincing a diverse population to embrace vaccination,” he stated.

Denmark continues to enjoy robust confidence in its governmental and health institutions, currently ranked first in public trust by Transparency International. In turn, this commitment has contributed to high childhood vaccination rates, with approximately 96% of Danish children vaccinated against diphtheria, tetanus, and pertussis, contrasting with only 80% in the United States, which ranks 28th in public trust levels.

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  • Vaccine/
  • Infectious Disease

Source: www.newscientist.com

One Smallpox Vaccine Dose Offers Continued Protection against Smallpox.

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There are few high-quality studies on the effectiveness of the smallpox vaccine against smallpox.

Emanuele Contini/Nuru Photo via Getty Images

One dose of one type of smallpox vaccine appears to reduce the risk of getting smallpox by about 60 percent, although this can vary depending on mutations of the virus.

Cases of MPOX, formerly known as monkeypox, are rapidly increasing in the Democratic Republic of Congo, driven by a variant called lineage Ib. The vaccine used to prevent MPOX was originally developed for smallpox, and although the two viruses are related, it is unclear whether it is specifically effective against MPOX.

For more information, Sharmistha Mishra Researchers at the Institute for Clinical Evaluative Sciences in Toronto, Canada, in collaboration with colleagues, focused on a vaccine called MVA-BN, also known as JYNNEOS, Imvanex, and Imvamune, which was the most widely used smallpox vaccine in Western countries during the 2022 smallpox outbreak caused by the clade IIb variant.

Studies have shown that the effectiveness of MVA-BN for mpox varies widely, from 36% to 86%. This range is likely because the studies are observational and compare results in people of different ages, locations, and health conditions.

A randomized controlled trial is being conducted among gay, bisexual and other men who have sex with men, who made up the majority of infections in Western countries during the 2022 outbreak.

Meanwhile, Mishra's team tried to mimic a randomized controlled trial using existing medical data. The researchers studied more than 6,000 Canadian men who were deemed to be at high risk for infection in 2022. About half received one dose of MVA-BN, and the rest did not receive the mpox vaccine. The two groups of men were matched by factors such as age and location, Mishra said.

While the official MVA-BN vaccination schedule calls for two doses administered at least 28 days apart, Mishra said the Canadian government initially opted for a one-dose vaccination protocol to spread the shots among as many at-risk people as possible.

During a follow-up period of approximately 80 days, 50 men in the unvaccinated group were diagnosed with MPOX compared to 21 in the vaccinated group, suggesting that MVA-BN reduced the risk by 58 percent.

This suggests that one dose is enough to provide protection. Adam Hacker At the London Coalition for Infectious Disease Preparedness Innovations Corinne Goertz van Kessel “Scientifically, we know that two doses are more effective,” Hacker told Erasmus MC in the Netherlands.

Geerts van Kessel says the team's approach was a good way to mimic a randomized controlled trial, but it is unclear whether some of the men, who are older than their mid-50s, were vaccinated when smallpox was a threat, which could have influenced their immune response to the 2022 MVA-BN.

Studying how the vaccine affects the severity of disease after infection with MPOX will also help assess the vaccine's overall effectiveness, she says.

It's also unclear how effective the drug is specifically against lineage Ib, Goertz van Kessel says, but both she and Hacker expect MVA-BN to be at least somewhat effective against that variant as well as it is against lineage IIb, which continues to circulate in West and Central Africa.

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Source: www.newscientist.com