Risk factors for severe Covid-19 breakthrough infections: an observational longitudinal study

Abstract

Background The drive to vaccinate large populations is nowadays the main instrument for combating the pandemic and preventing serious disease and death. However, breakthrough infection (post-vaccination infection) still happens after vaccination among fully vaccinated people. We aimed to assess the severity outcomes and to determine its associated factors among vaccinated COVID-19 cases in the governorate of Sousse, Tunisia. Methods We carried out a five-month observational longitudinal study including all the population of Sousse. Confirmed infections of SARS-CoV-2 and the vaccination status are recorded in the daily COVID- 19 database of the Regional Office of the Tunisian Ministry of Health. We included all post-vaccination COVID-19 cases for the analysis of the COVID-19 serious outcomes. Data were collected via 15-min telephonic call interviews conducted by trained interviewers. Descriptive analysis with calculating incidence rates of confirmed COVID-19 cases per 100,000 inhabitants was conducted. In binary logistic regression, adjusted odds ratios along with 95% intervals confidence were performed to determine factors related to severe or critical COVID-19. Results As of 31 July 2021, 107,545 persons over 19 years old have received at least one dose of COVID-19 vaccination. Among the vaccinated population, we traced and included 765 breakthrough infection cases, and the incidence rate was 711.3 per week. The majority were female (sex-ratio = 0.8), and the average age of the overall cases was 55.7 years. The prevalence of severe or critical cases in vaccinated COVID-19 patients occurs in 10.8% of cases. Patients with a medical history of cardiovascular diseases had more than two times increased odds to have a severe or critical disease. We also found the highest self-estimation of adherence to preventive measures was inversely correlated to serious cases and having an incomplete vaccination schema was strongly associated with complications. Conclusions We tried to provide evidence about the breakthrough infections to improve measures of prevention and control of COVID-19. Boosting immunity for vulnerable patients added to maintaining and promoting preventive measures are not only essential to prevent severe cases of breakthrough infections of COVID-19, but also other influenza-like diseases.

Prevalence, Clinical Profile and Determinants of COVID-19 Vaccination and SARS-CoV-2 Breakthrough Infection in Douala, Cameroon

“…In Qatar, Butt and colleagues 39 found an increased risk of severe COVID-19 and deaths in aged patients with vaccine breakthrough infection. Similar findings were also reported in Tunisia and Italy 40,41 . Other factors such as waning immunity, type of vaccines and SARS-CoV-2 variants (e.g., Omicron, Delta) can also modulate natural history of infection and thus shaped risk of vaccine breakthrough infection in populations [42][43][44][45] , especially in vulnerable groups such as elderly people, even in whom booster vaccine dose can fail to prevent breakthrough infection as recently reported 46 .…”

SARS-CoV-2 Vaccine Breakthrough Infections and the Assessment of Pre and Post- vaccination Attitude among Healthcare Workers towards the Practice of Safety Precautions in South West, Nigeria

“…Our study indicated that the incidence of COVID-19 breakthrough infection was higher among people who are fully vaccinated but without booster doses compared to fully vaccinated persons with booster doses. This was consistent with findings in other studies 22 Remarkably, from Table 9, 5 out of the 15 respondents that tested positive for covid-19, had been fully vaccinated. However, all 5 of them did not practice safety measures after vaccination.…”

A Pictorial Essay Describing the CT Imaging Features of COVID-19 Cases throughout the Pandemic with a Special Focus on Lung Manifestations and Extrapulmonary Vascular Abdominal Complications

“…The Delta variant caused more severe disease and was less susceptible to vaccines than previous lineages [37] (Figure 14). Nevertheless, several studies showed that pneumonia severity was lower in vaccinated than in unvaccinated patients [37,[87][88][89][90][91]96,97]. Lee et al [96] reported that the proportion of patients with negative CT scans was significantly greater in the fully vaccinated group than in the unvaccinated group.…”

“…Lee et al [96] reported that the proportion of patients with negative CT scans was significantly greater in the fully vaccinated group than in the unvaccinated group. Verma et al [97] reported that the mean CT severity score was significantly lower in completely vaccinated patients in comparison to incom- Nevertheless, several studies showed that pneumonia severity was lower in vaccinated than in unvaccinated patients [37,[87][88][89][90][91]96,97]. Lee et al [96] reported that the proportion of patients with negative CT scans was significantly greater in the fully vaccinated group than in the unvaccinated group.…”