A smallpox vaccine proven to protect against monkeypox has met with high demand around the world, prompting health officials to warn against repeating the uneven distribution seen during the Covid pandemic.
While monkeypox has long been endemic in parts of west and central Africa, there have been outbreaks around the world since May.
It has led to a scramble over doses of the world’s only approved monkeypox vaccine, made by Danish drugmaker Bavarian Nordic.
Here is the current state of affairs regarding the effectiveness and availability of the vaccine.
– 85% protection ‘about’ –
The vaccine, called MVA-BN and marketed as Jynneos in the US and Imvanex in Europe, was originally developed to combat smallpox.
Both viruses belong to the orthopoxvirus family.
Olivier Schwartz, head of the Department of Viruses and Immunity at France’s Pasteur Institute, said the viral proteins for monkeypox and smallpox are 90-95 percent similar.
“So a proven strategy is to use a very similar vaccine to block it,” he said.
Although there is not yet extensive data on the protection of Bavarian Nordic’s vaccine against monkeypox, previous research has shown that it is highly effective.
“The 85 percent coverage figure comes from field studies in the DRC in the 1980s and 1990s and is fairly approximate,” Schwartz said.
He added that studies on healthcare workers in 2018 and experiments on macaques showed the vaccine can be effective even if a patient has contracted monkeypox.
And people who received a smallpox vaccine dose before 1980 also have some immunity to monkeypox, although its extent and duration are uncertain.
Schwartz said studies in the 2000s found that about 30 percent of those who had been vaccinated two decades earlier still had antibodies to smallpox.
He added that a booster dose would “reactivate cellular immunity even after 20 to 40 years.”
However, Yannick Simonin, a virologist at the University of Montpellier, warned that immunity “decreases over time and the persistence of neutralizing antibodies to monkeypox has never been evaluated.”
– 350,000 doses to “undisclosed” nation –
Bavarian Nordic partnered with the US health authorities in 2003 and has already shipped 30 million doses to the country.
Since monkeypox began spreading outside of Africa in May, the company has announced plans to 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, meaning it will take months to be ready for use, according to the World Health Organization.
It has been difficult to determine the exact number of shares held by countries, which sometimes refused to disclose numbers – angering some NGOs and politicians.
Bavarian Nordic, which can produce up to 30 million cans a year, has also been reluctant to disclose where it sends them.
On Wednesday, the company announced it would ship 350,000 cans to an “unknown” country in Asia-Pacific.
Two other smallpox vaccines, ACAM2000 and LC16, are currently being evaluated for efficacy against monkeypox.
The United States currently stocks more than 100 million doses of ACAM2000, but it is thought to cause more side effects than newer-generation vaccines.
Emergent BioSolutions, which makes 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 equity” –
Although Africa is the continent that has long battled monkeypox, it has yet to receive vaccine doses.
There have been more than 3,000 confirmed cases of monkeypox in Africa this year, while doctors say around 70 deaths have been linked to the disease.
The WHO has called on countries that have vaccines to share and urged the world not to repeat the disparity in access to Covid vaccines between rich and poor countries.
Meg Doherty, director of WHO’s global HIV, hepatitis and sexually transmitted infection programs, said Sunday that 35 countries had applied for access to the monkeypox vaccine.
She told a meeting at the International AIDS Conference in Montreal that there was “a very possible risk” that it would be rich countries requesting the doses.
“We want justice,” she added.
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