As countries work hard to get everyone vaccinated, fake COVID-19 vaccines are making their way to unsuspecting patients.

Recently, police in the Indian state of Kolkata arrested a man running a fake COVID-19 vaccination drive. And, according to a recent news report, the problem might widespread. “China has been clamping down on counterfeit versions of its domestically produced vaccines, while Mexico and Poland have reported counterfeits of Pfizer vaccines being given to people for $1000 each. Mexican customs officials have also seized vials of fake Sputnik V vaccine destined for Honduras,” the author wrote in the news report.

Fake medicines is a booming market, estimated to be worth more than $4 billion globally, according to the Organisation for Economic Co-operation and Development (OECD). Now, with the COVID-19 pandemic still raging in most countries, fake COVID-19 vaccines as well as other medications and products are a growing problem.

According to Pernette Bourdillon Esteve, the acting team lead for the World Health Organization’s department of incidents and substandard / falsified medical products, since the pandemic started there has been a growing volume of COVID-19 fake medicines being sold, particularly in developing countries. Likewise, the Interpol also recently reported an increase in fake medical products related to COVID-19.

These fake medicines include products that may be contaminated, contain the wrong or no active ingredient, or may be out-of-date.

“Best case scenario they [fake medicines] probably won’t treat the disease for which they were intended”, Dr Esteve said in a news release. “But worst-case scenario they’ll actively cause harm, because they might be contaminated with something toxic,” he added.

According to a WHO report, up to 10% of medical products sold in developing countries are substandard or falsified.

Regarding fake COVID-19 vaccines, there are several different ways these products can enter the supply chain. According to Prashant Yadav, a health care supply chains expert from Harvard Medical School, in the USA, fake vaccines can be introduced at different stages.

“The way vaccine supply chains are organised, there are multiple points of vulnerability,” Yadav said in a news report. “The [higher the] number of hops and storage points there are, the greater are the risks in falsified or counterfeit products entering the supply chain, especially for products like COVID-19 vaccines — the demand far outstrips supply,” he said.

Esteve says it is difficult to assess the harm caused by these products. Often, a fake vaccine will cause no toxic reaction, but it will fail to protect or prevent illness. Other products, however, may cause harm.