Growing your own in times of crisis: the role of home food growing in perceived food insecurity and well-being during the early COVID-19 lockdown: [version 2;peer review: 2 approved]

Household food insecurity and poor well-being have increased during the coronavirus disease 2019 (COVID-19) pandemic and resulting lockdown measures. Home food growing has been associated with improved food access and well-being, but it is unknown what role it plays during food supply crises and lockdown. It is also unclear how home food growing and social restrictions may affect opinions about growing food in urban areas (i.e., urban agriculture [UA]). A cross-sectional online survey was conducted during the UK national lockdown in March-April 2020 to measure home food growing, perceived food insecurity, well-being, and opinions of UA. The participants were 477 UK-based adults (369 female, mean age 39.57 years ± 13.36);152 participants were engaged in home food growing prior to the pandemic. Responses were compared to data collected from a separate sample of participants before the pandemic (N = 583) to explore potential shifts in opinions about UA. Participants who engaged in home food growing had lower levels of food insecurity (U ­= 19894.50, z = -3.649, p<.001, r = -.167) and higher well-being (U = 19566.50, z = -3.666, p<.001, r = -.168) than those not engaged in home food growing. Perceived food insecurity partially mediated the relationship between home food growing and well-being;home food growing was associated with less food insecurity, which in turn was associated with better well-being. There were no differences in opinions of UA compared to the sample of participants from before the pandemic. Home food growing may have had a protective effect over perceived food security and well-being in the early stages the pandemic. Opinions of UA were positive and unchanged compared to data collected pre-pandemic. Policies that support home food growing and access to suitable growing spaces and resources may be beneficial for food system resilience and well-being.

SARS-CoV-2-specific memory B cells can persist in the elderly who have lost detectable neutralizing antibodies.

Memory B cells (MBCs) can provide a recall response able to supplement waning antibodies (Abs) with an affinity-matured response better able to neutralize variant viruses. We studied a cohort of elderly care home residents and younger staff (median age of 87 years and 56 years, respectively), who had survived COVID-19 outbreaks with only mild or asymptomatic infection. The cohort was selected because of its high proportion of individuals who had lost neutralizing antibodies (nAbs), thus allowing us to specifically investigate the reserve immunity from SARS-CoV-2-specific MBCs in this setting. Class-switched spike and receptor-binding domain (RBD) tetramer-binding MBCs persisted 5 months after mild or asymptomatic SARS-CoV-2 infection, irrespective of age. The majority of spike- and RBD-specific MBCs had a classical phenotype, but we found that activated MBCs, indicating possible ongoing antigenic stimulation or inflammation, were expanded in the elderly group. Spike- and RBD-specific MBCs remained detectable in the majority of individuals who had lost nAbs, although at lower frequencies and with a reduced IgG/IgA isotype ratio. Functional spike-, S1 subunit of the spike protein- (S1-), and RBD-specific recall was also detectable by enzyme-linked immune absorbent spot (ELISPOT) assay in some individuals who had lost nAbs, but was significantly impaired in the elderly. Our findings demonstrate that a reserve of SARS-CoV-2-specific MBCs persists beyond the loss of nAbs but highlight the need for careful monitoring of functional defects in spike- and RBD-specific B cell immunity in the elderly.

Pre-existing polymerase-specific T cells expand in abortive seronegative SARS-CoV-2.

Individuals with potential exposure to severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) do not necessarily develop PCR or antibody positivity, suggesting that some individuals may clear subclinical infection before seroconversion. T cells can contribute to the rapid clearance of SARS-CoV-2 and other coronavirus infections1-3. Here we hypothesize that pre-existing memory T cell responses, with cross-protective potential against SARS-CoV-2 (refs. 4-11), would expand in vivo to support rapid viral control, aborting infection. We measured SARS-CoV-2-reactive T cells, including those against the early transcribed replication-transcription complex (RTC)12,13, in intensively monitored healthcare workers (HCWs) who tested repeatedly negative according to PCR, antibody binding and neutralization assays (seronegative HCWs (SN-HCWs)). SN-HCWs had stronger, more multispecific memory T cells compared with a cohort of unexposed individuals from before the pandemic (prepandemic cohort), and these cells were more frequently directed against the RTC than the structural-protein-dominated responses observed after detectable infection (matched concurrent cohort). SN-HCWs with the strongest RTC-specific T cells had an increase in IFI27, a robust early innate signature of SARS-CoV-2 (ref. 14), suggesting abortive infection. RNA polymerase within RTC was the largest region of high sequence conservation across human seasonal coronaviruses (HCoV) and SARS-CoV-2 clades. RNA polymerase was preferentially targeted (among the regions tested) by T cells from prepandemic cohorts and SN-HCWs. RTC-epitope-specific T cells that cross-recognized HCoV variants were identified in SN-HCWs. Enriched pre-existing RNA-polymerase-specific T cells expanded in vivo to preferentially accumulate in the memory response after putative abortive compared to overt SARS-CoV-2 infection. Our data highlight RTC-specific T cells as targets for vaccines against endemic and emerging Coronaviridae.