Memories are awakened: Do we have to be vaccinated against smallpox again?

Anyone in their 50s today still got it as a child: the vaccination against smallpox.

Memories are awakened: Do we have to be vaccinated against smallpox again?

Anyone in their 50s today still got it as a child: the vaccination against smallpox. After the outbreak of monkeypox, the question arises as to whether this might be necessary again.

To this day, the scar on the upper arm of many adults bears witness to this: In 1967, the World Health Organization (WHO) started a worldwide vaccination campaign against smallpox, during which billions of people were vaccinated. It was the beginning of the end of the disease, also known as smallpox. It had raged for thousands of years before. Smallpox-like rashes have even been found on Egyptian mummies. According to the US disease control agency CDC, three out of ten infected people died. Survivors were often left with scars.

The WHO declared the eradication of smallpox as early as 1980; the last natural case was recorded three years earlier. Since the end of smallpox vaccinations - the obligation to have the first vaccination was lifted in Germany in 1976 and in East Germany in 1982 - fewer and fewer people are immune to the variola virus, which causes smallpox. With the currently unusual accumulation of monkeypox cases in Western countries due to a related pathogen, the question arises after the experience with Covid-19: Is another broad vaccination campaign needed or is that enough for certain groups?

There are no approved vaccines specifically against monkeypox in Europe. However, experts assume that conventional smallpox vaccines offer some protection. These have a very long history. The first well-documented successful vaccination against smallpox was done by the English country doctor Edward Jenner in 1796: he first administered cowpox viruses to a boy, a pathogen related to smallpox that causes less serious illness. Some time later, Jenner repeatedly exposed the child to the smallpox virus - and it went well, the boy did not get sick. According to Chinese sources, forms and attempts at smallpox immunization have existed for much longer, according to a conference report on the eradication of smallpox - for at least 1000 years.

Even after the smallpox was eradicated, people were again aware of the danger of smallpox: due to the attack on the World Trade Center in the USA, many countries stocked up on smallpox vaccine for fear of bioterrorism. Real human pox viruses capable of replication are stored in the USA and Russia, as the virologist Norbert Nowotny from the Institute of Virology at the University of Veterinary Medicine in Vienna said. "In retrospect, however, one has to admit that the fears of bioterrorism after 2001 were irrational. After all, the use of smallpox as a weapon would be completely uncontrollable."

The federal government has stored about 100 million doses of smallpox vaccine, according to a report for the Bundestag health committee. However, due to the expected side effects, this vaccine is not suitable for use against monkeypox, said Federal Health Minister Karl Lauterbach.

"The older smallpox vaccine has many side effects, and it also contains reproductive viruses that could spread in the body of immunocompromised people," said Stefan Kaufmann, director emeritus at the Max Planck Institute for Infection Biology in Berlin. According to the Viennese specialist in vaccination and travel medicine, Herwig Kollaritsch, about a quarter of the population would no longer be vaccinated today due to contraindications such as immune deficiencies.

There is also a newer smallpox vaccine that is based on a further development by the microbiologist Anton Mayr in Bavaria in the 1960s: A vaccine virus weakened in the laboratory is used to generate an immune response against smallpox, said Kollaritsch. Experts speak briefly of MVA vaccination (MVA: Modified Vaccinia Virus Ankara). "This vaccination was used for a while in the 1960s, but never on a large scale. It is better tolerated, the virus can no longer reproduce," said Kollaritsch, who is a member of the Austrian counterpart to the Standing Vaccination Commission (STIKO). There is also no vaccination scar.

With the vaccine, he sees the problem of a fairly uncertain vaccination effectiveness in practice in view of the eradicated disease. "But one can assume with a probability bordering on certainty protection." The MVA vaccine that has been approved in the EU for adults against smallpox since 2013 is called Imvanex and comes from the German-Danish company Bavarian Nordic. It is already approved for monkeypox in the United States. The WHO recently pointed out that it is not universally available. British health authorities have recently given more than 1,000 doses of it to contacts of people infected with monkeypox, according to the UK Health Security Agency.

Germany is also making provisions for the event that such so-called ring vaccinations should become necessary in the event of contact with the sick: Lauterbach announced on Tuesday that up to 40,000 doses of Imvanex would be ordered as a prophylactic. There are no concrete plans to use this as yet. "We could use this vaccine immediately if it became necessary," said Lauterbach.

At best, Kollaritsch sees the newer vaccine as a tool to vaccinate people who are at high risk of being exposed to the pathogen. As an example, he cites the staff of special isolation wards that care for infected people. "For the general public, this vaccination would be nonsense. Monkeypox is much more harmless than smallpox and of much lesser importance in terms of the epidemiology of infection. We also have to remember that very good therapy is available for infected people." Virologist Nowotny also emphasized: “There is a huge difference between monkeypox and corona. This time it will not be a pandemic. I assume that the spook will be over in a few weeks to a few months.”

The causative agent of monkeypox is a DNA virus - that means it is much slower than Sars-CoV-2 and hardly mutates. Variants will therefore not be seen so quickly. Nor does he assume that vaccines need to be specially adapted for monkeypox. In the literature, the mortality rate for the West African strain of monkeypox, which has so far been proven to be more common in Europe, is one percent: "In western countries, however, lower values ​​can be assumed."

The head of the Standing Vaccination Commission (STIKO), Thomas Mertens, recently said on SWR: "I don't think it makes sense to think about vaccinating the entire population against smallpox right now."

The Robert Koch Institute (RKI) stated that according to current knowledge, close contact is required for pathogen transmission, "so it can currently be assumed that the outbreak will remain limited". Isolation or quarantine is recommended for infected people and their close contacts. From an expert's point of view, contacts of infected people must be closely tracked. But that can be challenging: According to the RKI, the incubation period is 5 to 21 days. According to the RKI, people with several sexual partners have a higher risk of infection than others. Especially with them, anonymous contacts may also play a role.

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