The European Union's drug regulator has launched safety probes into the mRNA COVID-19 vaccines produced by both Pfizer and Moderna because of a possible association between them and skin and kidney conditions.

The European Medicines Agency, or EMA, announced the action this week after suspected side effects were reported in a "small number "of vaccinated individuals.

The EMA launched two probes, one for the Pfizer mRNA jab and another for the Moderna shot, and both will center on the same three alleged adverse reactions. One is a skin condition called erythema multiforme, the symptoms of which include round skin lesions that may also affect mucous membranes in internal body cavities.

The other two conditions affect the kidneys. Glomerulonephritis involves inflammation of small filters in the kidneys. Nephrotic syndrome is a disorder that causes the kidneys to leak too much protein into urine.

The EMA said no causal link between the vaccines and the conditions had been established. The regulator said it had requested "further data and analysis" from both Pfizer and Moderna to support the ongoing assessment.

"We take adverse events that are potentially associated with our COVID-19 vaccine, BNT162b2, very seriously," Pfizer said in a statement seen by pharmaceutical industry news outlet FiercePharma. "We closely monitor all such events and collect relevant information to share with global regulatory authorities."

The company said hundreds of millions of people have received its COVID-19 vaccine, and that, "serious adverse events that are unrelated to the vaccine are unfortunately likely to occur at a similar rate as they would in the general population".

The Pfizer vaccine is the most widely used COVID-19 shot in Europe, making up around two-thirds of jabs administered in the majority of EU nations. The EU pivoted toward the distribution of mRNA jabs after the EMA recommended a pause on the roll out of the viral vector vaccine produced by AstraZeneca due to a possible link to rare blood disorders.

The EMA did not say how many cases of the skin and kidney conditions had been reported and instead provided figures for total incidents of side effects of any kind. The regulator said it has followed up on 48,788 cases of suspected side effects out of 43.5 million Moderna shots administered in the EU, and 244,807 cases of possible side effects following 330 million doses of Pfizer given out in the region.

"These reports describe suspected side effects in individuals, i.e. medical events observed following the use of a vaccine," the regulator said in a statement. "The fact that someone has had a medical issue or died after vaccination does not necessarily mean that this was caused by the vaccine. This may have been caused, for example, by health problems not related to the vaccination."

Both the EMA and the World Health Organization have stressed that the benefits of getting vaccinated outweigh the risks of possible side effects.