More research needed into Long COVID-like adverse events after COVID-19 vaccination


The Netherlands Pharmacovigilance Centre Lareb has received reports of a combination of adverse events similar to Long COVID. There is insufficient evidence for a possible link with the COVID-19 vaccines. Lareb advises more epidemiological, clinical and immunological research.

Reports with adverse events similar to Long COVID
After an extensive exploratory analysis of reports of adverse events that lasted longer than 6 months and that arose within 28 days after vaccination, 78 reports have been highlighted in which there is a combination of typical adverse events similar to Long COVID.

As with Long COVID, the combinations of symptoms are very diverse. Frequently mentioned adverse events in various combinations are: shortness of breath, fatigue, malaise, chest pain, palpitations, dizziness, headache, muscle complaints and joint complaints. Also mentioned are: brain fog, difficulty thinking, reduced ability to concentrate, difficulty finding words, inability to deal with stimuli and memory loss. Several reporters describe that they are unable to function normally on a daily basis.

Medical examination was carried out in 41 of the 78 reports (53%). In 16 of the 78 reports (21%), a diagnosis was mentioned by the reporter. Long COVID was mentioned in 11 and chronic fatigue syndrome in 3 reports. In the remaining 62 of the 78 reports (80%), no diagnosis was made or this is unknown.

Insufficient evidence for a link with the COVID-19 vaccines
In approximately half of these reports, no medical research has been conducted into the possible causes of the adverse events, or this is not known. It is therefore not clear whether there are possible other causes, such as a COVID-19 infection. Testing for COVID-19 has not always been performed. In addition, asymptomatic COVID-19 infection, or COVID-19 infection with mild symptoms can be a cause of Long COVID.

Lareb has informed the Dutch Medicines Evaluation Board (MEB) about these reports. The MEB shares the conclusion that there is currently insufficient evidence on a causal relation with the COVID-19 vaccines. If more data becomes available (spontaneous reports and/or epidemiological research), the MEB will review this.

The full report can be found here.