Protection Associated with Previous SARS-CoV-2 Infection in Nicaragua

Maier, Hannah E.; Balmaseda, Ángel; Saborío, Saira; Ojeda, Sergio; Barilla, Carlos; Sánchez, Nery; López, Roger; Plazaola, Miguel; Cerpas, Cristhiam; Bakel, Harm van; Kubale, John; Harris, Eva; Kuan, Guillermina; Gordon, Aubree

doi:10.1056/nejmc2203985

Cited by 14 publications

(16 citation statements)

References 5 publications

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“…All RT‐PCR and most ELISAs were performed at the Nicaraguan National Virology Laboratory, with a minority of 2020 annual samples processed at the University of Michigan. Sequencing information was described previously 6 …”

Section: Methodsmentioning

confidence: 99%

SARS‐CoV‐2 infection‐induced immunity and the duration of viral shedding: Results from a Nicaraguan household cohort study

Maier

Plazaola

López

et al. 2022

Influenza Resp Viruses

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Background: Much of the world's population has been infected with SARS-CoV-2. Thus, immunity from prior infection will play a critical role in future SARS-CoV-2 transmission. We investigated the impact of infection-induced immunity on viral shedding duration and viral load. Methods:We conducted a household cohort study in Managua, Nicaragua, with an embedded transmission study that closely monitors participants regardless of symptoms. Real-time reverse-transcription polymerase chain reaction (RT-PCR) and enzyme-linked immunosorbent assays (ELISAs) were used to measure infections and seropositivity, respectively. Blood samples were collected twice annually and surrounding household intensive monitoring periods. We used accelerated failure time models to compare shedding times. Participants vaccinated ≥14 days prior to infection were excluded from primary analyses.Results: There were 600 RT-PCR-confirmed SARS-CoV-2 infections in unvaccinated participants between May 1, 2020, and March 10, 2022, with prior ELISA data. Prior infection was associated with 48% shorter shedding times (event time ratio [ETR] 0.52, 95% CI: 0.39-0.69, mean shedding: 13.7 vs. 26.4 days). A fourfold higher anti-SARS-CoV-2 spike titer was associated with 17% shorter shedding (ETR 0.83, 95% CI: 0.78-0.90). Similarly, maximum viral loads (lowest cycle threshold [CT]) were lower for previously infected individuals (mean CT 29.8 vs. 28.0, p = 4.02 Â 10 À3 ), for adults and children ≥10 years, but not for children 0-9 years; there was little difference in CT levels for previously infected versus naïve adults aged above 60 years.Conclusions: Prior infection-induced immunity was associated with shorter viral shedding and lower viral loads, which may be important in the transition from pandemic to endemicity.

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Section: Methodsmentioning

confidence: 99%

SARS‐CoV‐2 infection‐induced immunity and the duration of viral shedding: Results from a Nicaraguan household cohort study

Maier

Plazaola

López

et al. 2022

Influenza Resp Viruses

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“…Over half of household activations (n=164, 55%) occurred from March 2021-December 2021, a period when multiple variants circulated, and delta predominated. [24] Additionally, there were 29 (10%) participating households in March 2020-Febuary 2021 and 104 (35%) households in January 2022-June 2022. Overall, transmission occurred in 72.4% of households (Figure 1).…”

Section: Resultsmentioning

confidence: 99%

“…We also note that these results are from a community where most were infected with SARS-CoV-2 prior to the availability of SARS-CoV-2 vaccines. [24] Although adults in other settings may have been vaccinated before their first SARS-CoV-2 infection, most children have not been. [6][7][8][9] However, both infection then vaccination and vaccination then infection produces broad, hybrid immunity to SARS-CoV-2 with no observed differences by sequence.…”

Section: Discussionmentioning

confidence: 99%

Infection-induced immunity is associated with protection against SARS-CoV-2 infection, but not decreased infectivity during household transmission

Frutos

Kuan

López

et al. 2022

Preprint

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Background Understanding the impact of infection-induced immunity on SARS-CoV-2 transmission will provide insight into the transition of SARS-CoV-2 to endemicity. Here we estimate the effects of prior infection induced immunity and children on SARS-CoV-2 transmission in households. Methods We conducted a household cohort study between March 2020-June 2022 in Managua, Nicaragua where when one household member tests positive for SARS-CoV-2, household members are closely monitored for SARS-CoV-2 infection. Using a pairwise survival model, we estimate the association of infection period, age, symptoms, and infection-induced immunity with secondary attack risk. Results Overall transmission occurred in 72.4% of households, 42% of household contacts were infected and the secondary attack risk was 13.0% (95% CI: 11.7, 14.6). Prior immunity did not impact the probability of transmitting SARS-CoV-2. However, participants with pre-existing infection-induced immunity were half as likely to be infected compared to naive individuals (RR 0.53, 95% CI: 0.39, 0.72), but this reduction was not observed in children. Likewise, symptomatic infected individuals were more likely to transmit (RR 24.4, 95% CI: 7.8, 76.1); however, symptom presentation was not associated with infectivity of young children. Young children were less likely to transmit SARS-CoV-2 than adults. During the omicron era, infection-induced immunity remained protective against infection. Conclusions Infection-induced immunity is associated with protection against infection for adults and adolescents. While young children are less infectious, prior infection and asymptomatic presentation did not reduce their infectivity as was seen in adults. As SARS-CoV-2 transitions to endemicity, children may become more important in transmission dynamics.

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“…In Nicaragua, the majority of the population has previously been infected with SARS-CoV-2, and many have also been vaccinated. [11] Given the older age distribution in the US we anticipate that similar levels of co-circulation may in fact lead to greater rates of illness and severe disease.…”

Section: Discussionmentioning

confidence: 99%