Availability and effectiveness of the monkeypox vaccine

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Paris (AFP)- A smallpox vaccine that protects against monkeypox has been in huge global demand, leading health authorities to warn of a repeat of the uneven distribution seen during the Covid pandemic.

While monkeypox had long been endemic in parts of West and Central Africa, since May outbreaks have broken out across the world.

This has prompted a rush for doses of the world’s only licensed monkeypox vaccine, which is produced by Danish drugmaker Bavarian Nordic.

Here is the current status of vaccine efficacy and availability.

– 85% ‘approximate’ protection –

Called MVA-BN and marketed as Jynneos in the United States and Imvanex in Europe, the vaccine was originally developed to fight smallpox.

Both viruses are part of the orthopoxvirus family.

Olivier Schwartz, head of the virus and immunity unit at France’s Pasteur Institute, said the viral proteins in monkeypox and smallpox were 90-95% similar.

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

Although there are not yet large-scale data on the protection of Bavarian Nordic’s vaccine against monkeypox, previous research has suggested that it is highly effective.

“The vaccine protection figure of 85% dates from field studies in the 1980s and 1990s in DR Congo and is quite approximate,” Schwartz said.

He added that studies of healthcare workers in 2018 and experiments with macaques indicated the vaccine could be effective even after a patient contracted monkeypox.


And people who received a dose of smallpox vaccine before 1980 also have some immunity to monkeypox, although its extent and duration remains unclear.

Schwartz said studies during the 2000s found that about 30% of people vaccinated two decades earlier still had smallpox antibodies.

He added that a booster dose would “reactivate cellular immunity, even after 20 to 40 years”.

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

350,000 doses to an “undisclosed” country

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

Since monkeypox began spreading outside of Africa in May, the company has said it will ship seven million more doses to the United States.

There are around 16 million doses of the vaccine in total worldwide, mostly in bulk form, which means it will take months before they are ready for use, according to the World Health Organization.

It has been difficult to determine the exact number of stocks held by countries, which have sometimes refused to reveal the figures, which has angered some non-governmental organizations and politicians.

Bavarian Nordic, which can produce up to 30 million doses a year, has also been reluctant to reveal where it sends them.

On Wednesday, the company said it would supply 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 effectiveness against monkeypox.

The United States currently has more than 100 million doses stockpiled of ACAM2000, but it is thought to cause more side effects than next-generation vaccines.

Emergent BioSolutions, which manufactures ACAM2000, told AFP it can currently produce more than 18 million doses a year – and could increase to 40 million a year if needed.

– “We want fairness” –

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

There have been more than 3,000 confirmed cases of monkeypox in Africa this year, while doctors say around 70 deaths are linked to the disease.

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

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

She told a meeting at the International AIDS Conference in Montreal that there was “a very possible risk” that rich countries would be asking for the doses.

“We want fairness,” she added.

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