Safety of Pfizer-BioNTech vaccine in a cohort of healthcare providers: Differences between naïve and previously infected by SARS-CoV-2.

INTRODUCTION: The Spanish Society of Immunology recently warned that a history of past COVID-19 could result in a higher incidence of adverse events (AEs) related to vaccination. We set out to analyze whether there were any differences in AEs between healthcare workers vaccinated for COVID-19 (either after the first or second dose) who had had a prior diagnosis SARS-CoV-2 infection at any time compared to those who had not had COVID-19 before vaccination. METHODS: This was a retrospective cohort study in a population of healthcare workers. AEs related to the first and second doses of the Pfizer vaccine were recorded. We compared the incidence of AEs and compared individuals with 0-3 different AEs to those with 4 or more AEs. The relative risks (RR) and their 95% confidence intervals were calculated. RESULTS: Past infection was associated with having more AEs after the first dose (p < 0.001), but not the second one (p = 0.476), as well as a higher incidence of AEs (p < 0.001). Common AEs that were statistically associated with past COVID infection included arthralgia, asthenia, fever, chills, headache, and myalgia (p ≤ 0.001). The RR for having an increased absolute number of different AEs was 1.18 (95 %CI [1.05, 1.33]) after the first dose and 1.05 (95 %CI [0.96, 1.14]) after the second dose. The maximum number of days between past infection and vaccination was 306. CONCLUSIONS: Our results showed that the incidence of AEs was higher in individuals with a history of prior COVID-19 infection.

The Influence of Infection and Colonization on Outcomes in Inpatients With COVID-19: Are We Forgetting Something?

The COVID-19 epidemic has been a great challenge to health systems and especially hospitals. A prospective observational epidemiological study was planned as of February 26, 2020 in a tertiary hospital in the Valencia region. The total number of patients followed up with complete information during the first year was 2,448. Among other variables, the comorbidities of the patients were collected (and grouped in the Charson index), the stay in the intensive care unit (ICU), the co-infections, and the colonizations. Data on nosocomial infections due to said virus were also collected. The median days from the onset of symptoms to diagnosis were 4 + 4.6, while an additional 4.4 days had to pass for the patients to be admitted to the ICU. The factors associated with a higher risk of death were those with coinfection, especially with Candida auris [odds ratio (OR): 4.6], a situation that also occurred in the ICU (OR: 3.18). Charlson Index comorbidity and C. auris colonization were also very important both in general hospitalization and in the ICU.