Immune thrombocytopenia (ITP) has been widely reported as a complication of SARS-CoV-2 infection, but to our knowledge, there have been no reports on the association of the COVID-19 vaccine with thrombocytopenia. Here, we report a case of secondary ITP in a patient who was recently immunised with the messenger RNA COVID-19 vaccine BNT162b2 (Pfizer–BioNTech).

Omicron is the most mutated SARS-CoV-2 variant—a factor that can affect transmissibility, disease severity, and immune evasiveness. Its genomic surveillance is important in cities with millions of inhabitants and an economic center, such as Mexico City. Results. From 16 November to 31 December 2021, we observed an increase of 88% in Omicron prevalence in Mexico City. We explored the R346K substitution, prevalent in 42% of Omicron variants, known to be associated with immune escape by monoclonal antibodies. In a phylogenetic analysis, we found several independent exchanges between Mexico and the world, and there was an event followed by local transmission that gave rise to most of the Omicron diversity in Mexico City. A haplotype analysis revealed that there was no association between haplotype and vaccination status. Among the 66% of patients who have been vaccinated, no reported comorbidities were associated with Omicron; the presence of odynophagia and the absence of dysgeusia were significant predictor symptoms for Omicron, and the RT-qPCR Ct values were lower for Omicron. Conclusions. Genomic surveillance is key to detecting the emergence and spread of SARS-CoV-2 variants in a timely manner, even weeks before the onset of an infection wave, and can inform public health decisions and detect the spread of any mutation that may affect therapeutic efficacy.

Background. Omicron is the most mutated SARS-CoV-2 variant that has emerged, resulting in viral phenotype alterations, which can affect transmissibility, disease severity, and immune evasiveness. Genomic surveillance of a highly transmissible variant is important in cities with millions of inhabitants and an economic center such as Mexico City. In this work, we describe the early effects of the Omicron variant in Mexico City, exploring its genomic profile and clinical description. Methodology. We sequenced SARS-CoV-2-positive samples in November and December 2021 using the public database GISAID. Haplotype and phylogenetic analyses were performed to genomically characterize Omicron. We used the Mexican federal database to explore the association with clinical information such as symptoms and vaccination status. Findings. The first case of Omicron was detected on November 16, 2022, and until December 31, 2021, we observed an increase from 88% in sequenced samples. Nineteen nonsynonymous mutations were found in the Omicron RBD, and we further explored the R346K substitution, which was prevalent in 42% of the samples and associated with immune escape by monoclonal antibodies. In the phylogenetic analysis, we found that there were several independent exchanges between Mexico and the world, and there was an event followed by local transmission that gave rise to most of the Omicron diversity in Mexico City. The haplotype analysis allowed us to observe that there was no association between haplotype and vaccination status. Of the patients with clinical data, 66% were vaccinated, none of the reported comorbidities were associated with Omicron, the presence of odynophagia and absence of dysgeusia were significant predictor symptoms for Omicron, and the Ct value on RT-qPCR was lower in Omicron. Conclusions. Genomic surveillance in highly populated and fast-moving urban regions such as Mexico City is key to detecting the emergence and spread of SARS-CoV-2 variants in a timely manner, even weeks before the onset of an infection wave, to detect patterns that can inform public health decisions. It is also necessary to continue sequencing to detect the spread of any mutation that may affect the therapeutic efficacy or guide it.

RESUMEN. Se realizó una simulación in situ del proceso de atención de paciente con diagnóstico de COVID-19 programado para una cirugía de urgencia. Se observó desde la llegada al Departamento de Urgencias y hasta su salida del quirófano. Se llevaron a cabo los protocolos previamente establecidos y se observó por áreas de oportunidad.