evidence: Intervention: Any type of COVID-19 vaccine. We included the following types of COVID-19 vaccines: BNT162b2 ("Pfizer/BioNTech"), AZD1222 ("Oxford-AstraZeneca"), mRNA-1273 ("Moderna"), and Ad26.COV2.S ("Janssen"). Vaccine doses can be administered before or after SARS-CoV-2 acute infection. [...] The second topic is to know if COVID-19 vaccines represent a risk for those individuals with ongoing long-COVID symptomatology. We identified eleven level III studies of moderate to high methodological quality investigating the impact of vaccine on individuals who had previously suffered from COVID-19 and developed long-COVID (infection-long COVID-vaccine design). The results here were less consistent, since 63% of the studies (n=7/11) found that vaccination improved ongoing symptoms of long-COVID, whereas 36% (n=4/11) reported small changes or even worsening in some patients. Again, the definition of long-COVID among the studies was inconsistent. This heterogeneity in the response against vaccines of individuals with long-COVID could be related to the complexity of this condition. For instance, Tsuchida et al.24 identified that people experiencing a worsening of long-COVID symptoms after vaccination are those also showing excessive immune response to vaccination, with higher increased rate of antibody titers. On the contrary, Peghin et al.24 observed that COVID-19 vaccines did not produce an altered humoral response in individuals with current long-COVID. Discrepancies between these studies could be related to the fact that numerous autoantibodies may be produced after SARS-CoV-2 infection43 and, accordingly, COVID-19 vaccines effects could be dependent on the host immune response. [...] Symptoms after COVID-19 vaccination in patients with post-acute sequelae of SARS-CoV-2