Long-term levels of protection of different types of immunity against the Omicron variant: a rapid literature review.

INTRODUCTION: With the emergence of newer SARS-CoV-2 variants and their substantial effects on the levels and duration of protection against infection, an understanding of these characteristics of the protection conferred by humoral and cellular immunity can aid in the proper development and implementation of vaccine and safety guidelines. METHODS: We conducted a rapid literature review and searched five electronic databases weekly from 1 November 2021 to 30 September 2022. Studies that assessed the humoral or cellular immunity conferred by infection, vaccination or a hybrid (combination of both) in adults and risk groups (immunocompromised and older populations) were identified. Studies were eligible when they reported data on immunological assays of COVID-19 (related to vaccination and/or infection) or the effectiveness of protection (related to the effectiveness of vaccination and/or infection). RESULTS: We screened 5103 studies and included 205 studies, of which 70 provided data on the duration of protection against SARS-CoV-2 infection. The duration of protection of adaptive immunity was greatly impacted by Omicron and its subvariants: levels of protection were low by 3-6 months from exposure to infection/vaccination. Although more durable, cellular immunity also showed signs of waning by 6 months. First and second mRNA vaccine booster doses increased the levels of protection against infection and severe disease from Omicron and its subvariants but continued to demonstrate a high degree of waning over time. CONCLUSION: All humoral immunities (infection-acquired, vaccine-acquired and hybrid) waned by 3-6 months. Cellular immunity was more durable but showed signs of waning by 6 months. Hybrid immunity had the highest magnitude of protection against SARS-CoV-2 infection. Boosting may be recommended as early as 3-4 months after the last dose, especially in risk groups.

Impact of COVID-19 on Food Security in Ethiopia.

Since the outbreak of COVID-19, its effects on different aspects of life have been subject to much research, including food security, a domain that has been of special concern in many low-income countries. Ethiopia has been facing many challenges related to food security for decades via drought, famine, and conflict. Within this context, this case study assessed the impact of the COVID-19 pandemic on food security in Ethiopia. Results show that the ongoing pandemic has negatively impacted different regions and at-risk groups in a heterogeneous manner. This has been mainly through disruptions in the Ethiopian food value chain and the relative failure of social security programmes to address the losses generated by COVID-19. The population in the capital city, Addis Ababa, was able to maintain the same level of food security despite income losses caused by the COVID-19 pandemic. However, at-risk groups such as refugees, internally displaced persons (IDPs), and conflict affected regions were seen to suffer significantly from food insecurity exacerbated by COVID-19. Furthermore, this paper particularly emphasizes the importance of considering contextual factors other than COVID-19, such as conflicts or climate change, when discussing the state of food security in Ethiopia.