BACKGROUND: The durability of heterologous COVID-19 vaccine effectiveness (VE) has been primarily studied in high-income countries, while evaluation of heterologous vaccine policies in low- and middle-income countries remains limited.
OBJECTIVE: We aimed to evaluate the duration during which the VE of heterologous COVID-19 vaccine regimens in mitigating serious outcomes, specifically severe COVID-19 and death following hospitalization with COVID-19, remains over 50%.
METHODS: We formed a dynamic cohort by linking records of Thai citizens aged ≥18 years from citizen vital, COVID-19 vaccine, and COVID-19 cases registry databases between May 2021 and July 2022. Encrypted citizen identification numbers were used to merge the data between the databases. This study focuses on 8 common heterologous vaccine sequences: CoronaVac/ChAdOx1, ChAdOx1/BNT162b2, CoronaVac/CoronaVac/ChAdOx1, CoronaVac/ChAdOx1/ChAdOx1, CoronaVac/ChAdOx1/BNT162b2, BBIBP-CorV/BBIBP-CorV/BNT162b2, ChAdOx1/ChAdOx1/BNT162b2, and ChAdOx1/ChAdOx1/mRNA-1273. Nonimmunized individuals were considered for comparisons. The cohort was stratified according to the vaccination status, age, sex, province location, month of vaccination, and outcome. Data analysis employed logistic regression to determine the VE, accounting for potential confounders and durability over time, with data observed over a follow-up period of 7 months.
RESULTS: This study includes 52,580,841 individuals, with approximately 17,907,215 and 17,190,975 receiving 2- and 3-dose common heterologous vaccines (not mutually exclusive), respectively. The 2-dose heterologous vaccinations offered approximately 50% VE against severe COVID-19 and death following hospitalization with COVID-19 for 2 months; however, the protection significantly declined over time. The 3-dose heterologous vaccinations sustained over 50% VE against both outcomes for at least 8 months, as determined by logistic regression with durability time-interaction modeling. The vaccine sequence consisting of CoronaVac/CoronaVac/ChAdOx1 demonstrated >80% VE against both outcomes, with no evidence of VE waning. The final monthly measured VE of CoronaVac/CoronaVac/ChAdOx1 against severe COVID-19 and death following hospitalization at 7 months after the last dose was 82% (95% CI 80.3%-84%) and 86.3% (95% CI 83.6%-84%), respectively.
CONCLUSIONS: In Thailand, within a 7-month observation period, the 2-dose regimens could not maintain a 50% VE against severe and fatal COVID-19 for over 2 months, but all of the 3-dose regimens did. The CoronaVac/CoronaVac/ChAdOx1 regimen showed the best protective effect against severe and fatal COVID-19. The estimated durability of 50% VE for at least 8 months across all 3-dose heterologous COVID-19 vaccine regimens supports the adoption of heterologous prime-boost vaccination strategies, with a primary series of inactivated virus vaccine and boosting with either a viral vector or an mRNA vaccine, to prevent similar pandemics in low- and middle-income countries.

BACKGROUND: Hospital staff members are most susceptible to the COVID-19 illness, which is currently prevented through vaccination. Hospital staff members also refuse vaccinations, albeit the underlying causes have not been identified. The study aimed to compare the severity of the symptoms of the disease on the body for health workers who took the coronavirus vaccine and those who did not take the vaccine.
METHODS: This cohort study aimed to estimate the of infection severity of vaccinated and unvaccinated health workers with Corona Virus in Mosul Hospital, Iraq. Data were obtained from the General Mosul Hospital, Nineveh, Iraq. The first of the three components of this questionnaire outlined the demographic characteristics. Second part: First group of unvaccinated Health care workers included those who had not received the COVID-19 immunization or had only gotten one dose of the vaccine; the second group included those who had received their first dose of Corona vaccine and the third group included those who had received two doses of Corona Vaccine. HCWs who got corona vaccine were included in the three-dose final group.
RESULTS: The study\'s findings indicate that as compared to the corona vaccination, the vaccinated experienced less severe infection symptoms and fewer dosage stays. The high share of healthcare workers among the 20- to 30-year-olds who received vaccinations accounts for the gender gap between the vaccinated and unvaccinated groups.
CONCLUSIONS: This study concluded that the results of the corona vaccine are not consistent among the various groups of HCWs. The acceptability of vaccinations is practically unanimous among nurses, but less so among doctors and other healthcare professionals.

We compared the clinical characteristics and outcome of vaccinated hospitalized COVID-19 patients with unvaccinated hospitalized COVID-19 patients. A retrospective cohort study was conducted at the Sindh Infectious Diseases Hospital and Research Center, Karachi, Pakistan. A total of 1407 hospitalized COVID-19 positive patients were included from April 2021 to March 2022, of which 812 (57.71%) were males. Of the 1407, 378 (26.87%) patients were vaccinated while 1029 (73.13%) were unvaccinated. Of the vaccinated patients, 160 (42.32%) were partially vaccinated while 218 (57.68%) were fully vaccinated (vaccine breakthrough infection). Fewer unvaccinated COVID-19 patients survived compared to vaccinated patients (62.5% vs. 70%, RR 0.89, 95% CI: 0.82-0.96, p-value = 0.004). Despite there being more vaccinated patients above 60 years of age (60.05% vs. 47.13%), their risk of mortality was lower by 43% (OR = 0.578; CI = 0.4201 to 0.7980, p = 0.0009). On survival analysis, vaccinated patients had better 30-day survival compared to unvaccinated patients (p = 0.028). Moreover, comparing waves 3-5, unvaccinated patients of wave 4, which was driven by the delta variant, had the worst survival (51.8%, p ≤ 0.001) while vaccinated patients of wave 3 (driven by the alpha variant) had the best survival (71.6%).

Measles is endemic in Somalia; recurrent outbreaks are reported annually. Under-five children are the most affected due to low immunization coverage, vitamin A deficiency, and malnutrition. The study aims to evaluate the demographical, clinical, and complication variations between vaccinated and unvaccinated hospitalized children with measles in the study hospital.
UNASSIGNED: A hospital-based retrospective cohort study was implemented between 10 October and 10 November 2022 by reviewing case record files following a well-structured checklist of admitted clinical features, demographic characteristics, history of measles immunization, and measles complication status. Descriptive statistics were used by presenting frequency and percentage for categorical and the mean score for continuous variables. χ2 and Fisher\'s exact test at P =0.05 were used to identify the proportions differences between vaccinated and unvaccinated cases.
UNASSIGNED: A total of 93 hospitalized measles children participated in the study. Over half were boys, the mean age in months was 20.9 (SD±7.28), and over two-thirds of the mothers/caregivers did not have formal education. Almost 9.7% of hospitalized measles children had one dose of the measles-containing vaccine, while none had two doses. The vaccinated cases had fewer ill with fewer complications than the unvaccinated cases. Fever, cough, rash, and Koplik\'s spots were clinical features associated with measles immunization status.
UNASSIGNED: Around one in ten hospitalized children had one dose of the measles vaccine. Vaccinated cases had fewer illnesses with few complications than unvaccinated cases. The paper highly emphasizes providing booster doses, improving vaccine logistics and storage, and following immunization schedules. In addition, conducting further multicentral high sample-size studies is highly required to identify whether vaccine inadequacy was due to host-related or vaccine-related factors.

UNASSIGNED: Breakthrough infections in fully vaccinated persons pose a major challenge to the ongoing vaccine campaign against SARS-CoV-2 globally.
UNASSIGNED: To investigate the occurrence of breakthrough infections and the association of Covid symptoms with the vaccination status of health care workers (HCWs).
UNASSIGNED: Done in Government Medical College, Patiala among Covid-positive HCWs who have received one or both doses of Covid vaccine, using pretested semi-structured validated Proforma and telephonic interview from April 1, 2021 to June 15, 2021.
UNASSIGNED: Among 3388 HCWs, 115 vaccinated HCWs (1st or 2nd dose) became Covid positive. Among vaccinated Covid positive HCWs, 54 received the first dose and 61 both doses. Breakthrough infections (≥14 days post 2nd dose) occurred in 4.6% (47 of 1021) HCWs. The vaccine is significantly protective as shown by an odds ratio of 0.27; thus, vaccinated HCWs are 73% less likely to get Covid infection as compared to non-vaccinated HCWs. There was no statistically significant difference between symptom profiles of cases whether they took one or both doses of vaccine, except headache. Only tiredness and headache were reported significantly higher in the unvaccinated group in comparison to vaccinated HCWs.
UNASSIGNED: Research is needed on tracking the immune response and viral genomic sequence of samples of vaccinated Covid-positive HCWs to have constant vigilance on remerging new strains of the SARS-CoV-2.

BACKGROUND: Monoclonal antibodies (mAb) prevent COVID-19 progression when administered early. We compared mAb treatment outcomes among vaccinated and unvaccinated patients during Delta wave and assessed the feasibility of implementing stricter eligibility criteria in the event of mAb scarcity.
METHODS: We conducted a retrospective observational study of casirivimab/imdevimab recipients with mild-to-moderate COVID-19 infection in an emergency department or outpatient infusion center (July 1-August 20, 2021). Primary outcome was all-cause hospital admission within 30 days post-treatment between vaccinated vs. unvaccinated patients during Delta surge in the Bronx, NY.
RESULTS: A total of 250 patients received casirivimab/imdevimab (162 unvaccinated vs. 88 vaccinated). The median age was 39 years for unvaccinated patients, and 52 years for vaccinated patients (p < 0.0001). The median number of EUA criteria met was 1 for unvaccinated and 2 for vaccinated patients (p < 0.0001). Overall, 6% (15/250) of patients were admitted within 30 days post-treatment. Eleven unvaccinated patients (7%) were admitted within 30-days compared to 4 (5%) vaccinated patients (p = 0.48).
CONCLUSIONS: All-cause 30-day admission was not statistically different between vaccinated and unvaccinated patients. When federal allocation of therapies is limited, programs must prioritize patients at highest risk of hospitalization and death regardless of vaccination status.