Fact-check: Is hantavirus a side effect of Covid-19 vaccine?

Is hantavirus pulmonary infection caused by the Covid-19 vaccine?

That’s what some social media posts have claimed, which just isn’t true. Hantavirus pulmonary infection is caused by some hantaviruses. Yet, some posts shared widely online misrepresented a document listing potential medical events after inoculation.

“List of Pfizer Covid jab side effects includes hantavirus pulmonary infection!” a May 7 post on Facebook claimed. The post shared a purported screenshot of submissions Pfizer filed with the US Food and Drug Administration in 2021 to obtain a biological licence for its vaccine. Such posts also went viral on X.

The reference to hantavirus pulmonary infection in the Pfizer document was on page four of the nine-page appendix, titled “List of Adverse Events of Special Interest”.

However, this does not mean that the vaccine causes hantavirus pulmonary infection, a spokesperson for Pfizer said in an email. A disclaimer on page six of the document makes a similar point. The document simply lists any medical event experienced by a person during the study period between December 2020, when the Pfizer-BioNTech Covid-19 vaccine was first authorised, and February 28, 2021, regardless of whether it was related to the vaccine, the spokesperson added.

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It was compiled using voluntary reports through various national reporting systems, such as the Vaccine Adverse Event Reporting System (VAERS) in the United States.

The appendix, which lists hantavirus pulmonary infection, includes any potential medical events that Pfizer would consider of special interest if they occurred during the study period. These adverse events are published in Pfizer’s product leaflet. Hantavirus is not mentioned.

No hantaviruses in ingredient of Pfizer vaccine

Some hantaviruses cause hantavirus pulmonary infection or syndrome, according to the US National Institutes of Health and the World Health Organization. There are no hantaviruses in the ingredient list of the Pfizer Covid vaccine, now called Comirnaty. According to Pfizer’s website, the Comirnaty shot does not contain live viruses.

Test tubes labelled "Hantavirus positive". File Photo/ Reuters

As of May 7, an outbreak of hantavirus on a Dutch-flagged cruise ship has killed three people. South Africa’s health ministry said on May 6 that the Andes strain of hantavirus was identified in two victims who had been evacuated from the ship to the country.

The World Health Organization said in an online factsheet that the Andes strain is the only hantavirus that has seen human-to-human transmission. Transmission remains uncommon and, when it does happen, is associated with “close and prolonged contact”, the WHO added.

The US Food and Drug Administration did not respond to a request for comment. An FDA spokesperson said in a previous Reuters fact-check that reports to VAERS post-vaccination “do not necessarily mean that a vaccine caused a health problem”. Anyone can submit a report, regardless of plausibility, added the spokesperson.

The Verdict

Misleading. Hantavirus pulmonary infection appeared in a list of possible medical events that would be considered of special interest if they occurred during the study period, regardless of whether the medical event was caused by the vaccine. Pfizer’s regulatory document lists events that were later found to have a causal effect, and this list does not include hantavirus pulmonary infection.

FAQs

1. Does the Pfizer Covid-19 vaccine cause hantavirus infection?

No. There is no evidence that the Pfizer Covid-19 vaccine causes hantavirus infection.

2. Why was hantavirus listed in Pfizer’s document?

It was included in a list of “adverse events of special interest”, meaning any medical condition reported during the study period, regardless of whether it was caused by the vaccine.

3. Does the Pfizer vaccine contain hantavirus or live viruses?

No. The Pfizer vaccine (Comirnaty) does not contain hantavirus or any live virus.

With inputs from agencies