Vaccine hesitancy promotes emergence of new SARS-CoV-2 variants

The duty of care and the right to be cared for: is there a duty to treat the unvaccinated?

Vaccine hesitancy or refusal has been one of the major obstacles to herd immunity against Covid-19 in high-income countries and one of the causes for the emergence of variants. The refusal of people who are eligible for vaccination to receive vaccination creates an ethical dilemma between the duty of healthcare professionals (HCPs) to care for patients and their right to be taken care of. This paper argues for an extended social contract between patients and society wherein vaccination against Covid-19 is conceived as essential for the protection of the right of healthcare providers to be taken care of. Thus, a duty of care is only valid when those who can receive vaccination actually receive it. Whenever that is not the case, the continuing functioning of HCPs can only be perceived as supererogatory and not obligatory.

COVID-19 Crisis in Brazil: Post-Vaccination Seroprevalence and Infection in More and Less Vaccinated Municipalities in a Northeastern State

BACKGROUND

Given the impact of the pandemic in Brazil, vaccination is essential to prevent illness and death. Thus, this study sought to compare, after vaccination, the circulation of SARS-CoV-2 and the response to vaccination in the least and most vaccinated municipalities of a Brazilian state during the height of the pandemic when the Omicron variant was dominant.

METHODS

We tested for the SARS-CoV-2 antigen and confirmed infection using an RT-qPCR and measured IgM and IgG antibodies in fully vaccinated participants from municipalities with higher and lower vaccination rates.

RESULTS

We showed that participants from the least vaccinated municipalities were more likely to have detectable IgM antibodies and a positive antigen/RT-qPCR result for SARS-CoV-2 than participants from the most vaccinated municipalities. There were no differences between the vaccines used (BNT162b2, Ad26.COV2.S, AZD1222, and CoronaVac) and antibody production.

CONCLUSIONS

Our study evaluated municipal vaccination coverage and its effects on mortality, infections, and anti-SARS-CoV-2 antibodies during a critical phase of the pandemic. The results suggest that higher vaccination coverage reduces acute cases and confers higher memory antibody levels against SARS-CoV-2. Even with a full vaccination schedule, individuals living in places with low vaccination rates are more susceptible to infection.

Climate-dependent effectiveness of nonpharmaceutical interventions on COVID-19 mitigation

Environmental factors have a significant impact on the transmission of infectious diseases. Existing results show that the novel coronavirus can persist outside the host. We propose a susceptible-exposed-presymptomatic-infectious-asymptomatic-recovered-susceptible (SEPIARS) model with a vaccination compartment and indirect incidence to explore the effect of environmental conditions, temperature and humidity, on the transmission of the SARS-CoV-2 virus. Using climate data and daily confirmed cases data in two Canadian cities with different atmospheric conditions, we evaluate the mortality rates of the SARS-CoV-2 virus and further estimate the transmission rates by the inverse method, respectively. The numerical results show that high temperature or humidity can be helpful in mitigating the spread of COVID-19 during the warm summer months. Our findings verify that nonpharmaceutical interventions are less effective if the virus can persist for a long time on surfaces. Based on climate data, we can forecast the transmission rate and the infection cases up to four weeks in the future by a generalized boosting machine learning model.

Drivers of vaccine hesitancy among vulnerable populations in India: a cross-sectional multi-state study

Objectives

India's Covid-19 vaccination campaign engaged frontline workers (FLWs) to encourage vaccination among vulnerable segments of society. The FLWs report encountering a variety of barriers to vaccination and are often unsuccessful despite multiple visits to the same person. This cross-sectional study aims to pinpoint which of these barriers drive vaccine hesitancy among these segments, to help streamline vaccine communication, including FLW training, to better safeguard the population.

Methods

Trained field enumerators contacted 893 individuals from five states across India and collected self-reported assessments of fifteen vaccination barriers (identified through discussions with FLWs), current vaccination status and future vaccination intentions, and covariates (demographics/comorbidities). Factor analysis of the fifteen barriers yielded two factors, one relating to fear of vaccine adverse effects and a second focused on peripheral concerns regarding the vaccine. The covariates significantly associated with current vaccination status were combined under a latent class regime to yield three cluster types (health access, financial strength, and demographics). The primary analysis examined the effect of the two barrier factors, the covariate clusters, and comorbidity, on current vaccination status and future vaccine intentions.

Results

Fear of vaccine adverse effects was the primary driver of vaccine hesitancy; peripheral concerns frequently mentioned by the FLWs had no impact. Although cluster membership and the presence of comorbidities predicted vaccine uptake, neither of them materially altered the effect of fear of vaccine adverse effects with the following exception: fear of adverse effects was not associated with vaccination status among young Muslim men.

Conclusion

Subject to limitations, these results indicate that interventions to decrease vaccine hesitancy should focus primarily on fear associated with vaccines rather than spend resources trying to address peripheral concerns.