Availability and efficacy of monkeypox vaccine

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Paris (AFP) – A smallpox vaccine that protects against monkeypox is in global demand, prompting health authorities to avoid a repeat of the uneven distribution seen during the Covid pandemic.

While monkeypox has long been endemic in parts of West and Central Africa, outbreaks have been reported worldwide since May.

It has sparked controversy over doses of the only approved monkeypox vaccine worldwide, produced by the Danish drugmaker Bavarian Nordic.

Here’s the current state of the game on vaccine effectiveness and availability.

– 85% protection “estimated” –

The vaccine, called MVA-BN and marketed as Jynneos in the US and Imvanex in Europe, was originally developed to fight smallpox.

Both viruses belong to the orthopoxvirus family.

Olivier Schwartz, head of the virus and immunity department at France’s Pasteur Institute, said the virus proteins for monkeypox and smallpox are 90-95 percent similar.

“So using a very similar vaccine to block it is a proven strategy,” he said.

Although there are no large-scale data on the protection of the Bavarian Nordic vaccine against monkeypox, previous studies have shown that it is effective.

“Field studies in the DR Congo in the 1980s and 1990s estimated vaccine protection rates of 85 percent,” Schwartz said.

He added that in 2018, research conducted on medical workers and experiments on macaques showed that the vaccine can be effective even after exposure to monkeypox.

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People who received a dose of the smallpox vaccine before 1980 are also immune to monkeypox, but the extent and duration remains unknown.

According to Schwartz, studies in the 2000s showed that about 30 percent of those vaccinated two decades earlier still had smallpox antibodies.

He added that the booster dose “reactivates cellular immunity even after 20-40 years.”

But Yannick Simonin, a virologist at the University of Montpellier, cautioned that “immunity declines over time and the persistence of antibodies against monkeypox has never been assessed.”

350,000 doses to “unexposed” people

Bavarian Nordic partnered with US health authorities in 2003 and has already delivered 30 million doses to the country.

The company said it will deliver seven million more doses to the United States since monkeypox began spreading outside of Africa in May.

According to the World Health Organization, around 16 million doses of the vaccine are available worldwide, mostly in bulk form, meaning it takes months before they are ready for use.

It has been difficult to determine the exact number of stocks held by countries that sometimes refuse to disclose the numbers, angering some NGOs and politicians.

Bavarian Nordic, which can produce up to 30 million doses a year, also declined to disclose where it was sending them.

On Wednesday, the company announced it would deliver 350,000 doses to an “undisclosed” country in the Asia-Pacific region.

Two other smallpox vaccines, ACAM2000 and LC16, are currently being studied to determine their efficacy against monkeypox.

There are currently more than 100 million doses of ACAM2000 in the United States, but it is believed to cause more side effects than newer-generation vaccines.

Emergent BioSolutions, which created ACAM2000, told AFP that it currently has the capacity to produce more than 18 million doses a year and could increase to 40 million annually if needed.

– “We want equality” –

Despite being a continent that has long struggled with monkeypox, Africa has yet to receive a dose of the vaccine.

There have been more than 3,000 confirmed cases of monkeypox in Africa this year, and doctors say about 70 people have been linked to the disease.

The WHO has called on countries with vaccines to share, urging the world not to repeat the disparity in access to Covid vaccines between rich and poor countries.

Meg Doherty, director of the WHO’s global program on HIV, hepatitis and sexually transmitted infections, said on Sunday that 35 countries had requested access to the monkeypox vaccine.

He told a meeting at the International AIDS Conference in Montreal that “it’s possible” rich countries will require doses.

“We want equality,” he added.

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