Since its emergence in 2019, severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has caused hundreds of millions of cases and continues to circulate globally. To establish a novel SARS-CoV-2 human challenge model that enables controlled investigation of pathogenesis, correlates of protection and efficacy testing of forthcoming interventions, 36 volunteers aged 18–29 years without evidence of previous infection or vaccination were inoculated with 10 TCID50 of a wild-type virus (SARS-CoV-2/human/GBR/484861/2020) intranasally in an open-label, non-randomized study

Studies have found an increased risk for cardiac complications after SARS-CoV-2 infection and mRNA COVID-19 vaccination, but few have compared these risks. Data from 40 health care systems participating in a large network found that the risk for cardiac complications was significantly higher after SARS-CoV-2 infection than after mRNA COVID-19 vaccination for both males and females in all age groups. These findings support continued use of recommended mRNA COVID-19 vaccines among all eligible persons aged =5 years.

In Milan, high wastewater SARS-CoV-2 loads were found when vaccination coverage was high and traditional surveillance indicators suggested limited SARS-CoV-2 prevalence. This result suggests that there was significant circulating virus in the population during this period, including among vaccinated individuals. The SARS-CoV-2 circulation among vaccinated individuals may create modest evolutionary pressure toward resistance to the host’s immune response, making variants with significant transmission advantages more competitive.

With the Omicron variant (B.1.1.529), SARS-CoV-2 infections and hospitalizations reached record levels. Children younger than 5 years may be especially vulnerable because they are not eligible for COVID-19 vaccination. We examined incidence rates and clinical outcomes of Omicron infection before and after Omicron became the predominant variant in the US. Results of this cohort study suggest that the incidence rate of SARS-CoV-2 infection with Omicron variant was 6 to 8 times that of Delta variant in children younger than 5 years, but severe clinical outcomes were less frequent than with Delta variant.

The outbreak of Coronavirus Disease 2019 (COVID-19) at the end of 2019 turned into a global pandemic. To help analyze the spread and evolution of the virus, we collated and analyzed data related to the viral genome, sequence variations, and locations in temporal and spatial distribution from GISAID. Information from the Wikipedia web page and published research papers were categorized and mined to extract epidemiological data, which was then integrated with the public dataset. Genomic and epidemiological data were matched with public information, and the data quality was verified by manual curation.

We estimated vaccine effectiveness (VE) of the BNT162b2 (Pfizer-BioNTech, https://www.pfizer.com) booster dose against SARS-CoV-2 infection and reduction of complications (hospitalization, severe disease, and death) among breakthrough cases in persons in Israel >16 years of age for <20 weeks. VE estimates reached 96.8% (95% CI 96.0%-97.5%) for persons 16-59 years of age and 93.1% (95% CI 91.8%-94.2%) for persons >60 years of age on week 3. VE estimates remained at these levels for 8 weeks in the 16-59 age group and 11 weeks in those >60. A slow decline followed, becoming more pronounced in the last 2-3 weeks of evaluation. Estimates in the last week of evaluation were 77.6% (95% CI 68.4%-84.2%) and 61.3% (52.5%-68.4%) for persons 16-59 years and >60 years.

We report wastewater surveillance for SARS-CoV-2 variants of concern by using mutation-specific, real-time PCR and rapid nanopore sequencing. This surveillance might be useful for an early warning in a scenario in which a new variant is emerging, even in areas that have low virus incidences.

We retrieved 8,837 records from the search strategy; 71 studies (61 clinical and 10 non-clinical studies, involving 17,719,495 pregnant persons and 389 pregnant animals, respectively) were included. Most studies (94%) were conducted in high-income countries and were cohort studies (51%). Less than 15% of studies were classified as high risk of bias. We identified nine COVID-19 vaccine studies, two preclinical studies, and seven involving 309,164 pregnant persons, mostly exposed to mRNA vaccines. Neither pregnancy outcomes nor reactogenicity exceeded the expected rates. The only exception was postpartum hemorrhage after COVID-19 vaccination reported by two studies. In conclusion, we found no safety concerns for currently administered COVID-19 vaccines during pregnancy.

VE against symptomatic infection was considerably lower during Omicron- versus Delta-predominance (70% vs. 95% among =18 year-olds). During Omicron-predominance, estimated 3-dose VE at <4 weeks post-vaccination was highest in 12-17 year-olds (89·7%), followed by =60 year-olds (87·8%) and 18-59 year-olds (77·4%), and declined to 84·4% at 4 to <8 weeks post-vaccination and 51·1% and 76·4% at 8 to <12 weeks post-vaccination, respectively. VE against hospitalization was high in all age groups and remained >90% among =60 year-olds and >75% among 18-59 year-olds at 8 to <12 weeks post-vaccination, while VE against severe illness among =60 year-olds was >95% at 8 to <12 weeks.

As the COVID Human Genetic Effort consortium (https://www.covidhge.com/), we have studied genetic and immunological determinants of life-threatening COVID-19 pneumonia1, multisystem inflammatory syndrome (MIS-C)2, resistance to SARS-CoV-2 infection3 and ‘COVID toes’4, and here we present our efforts to investigate post-acute COVID-19 syndrome, or ‘long COVID’.

Using the Israeli Ministry of Health database, we extracted data on 1,252,331 persons who were 60 years of age or older and eligible for the fourth dose during a period in which the B.1.1.529 (omicron) variant of SARS-CoV-2 was predominant. The number of cases of severe Covid-19 per 100,000 person-days (unadjusted rate) was 1.5 in the aggregated four-dose groups, 3.9 in the three-dose group, and 4.2 in the internal control group. Protection against confirmed infection appeared short-lived, whereas protection against severe illness did not wane during the study period.

We measured neutralization of the Omicron BA.1 variant pseudovirus by post-vaccination serum samples after two and three immunizations with the Pfizer/BioNTech162b2 SARS-CoV-2 mRNA (Pfizer/BNT162b2) vaccine, convalescent serum samples from unvaccinated individuals infected by different variants, and clinical-stage therapeutic antibodies. We found that titers against the Omicron variant were low or undetectable after two immunizations and in many convalescent serum samples, regardless of the infecting variant. A booster vaccination increased titers more than 30-fold against Omicron to values comparable to those seen against the D614G variant after two immunizations.

In this prospective cohort of frontline workers, a third mRNA vaccine dose provided strong (91%) protection against delta infection, similar to the findings of a study showing an effectiveness of 89 to 94% for three doses of mRNA vaccine against medically attended Covid-19 during a period when the delta variant was predominant.4 In contrast, our estimate of vaccine effectiveness of 60% for three doses against omicron infection was lower than the corresponding effectiveness of three doses against medically attended Covid-19 (82 to 90%) in the same study.

Since its emergence in 2019, severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has caused hundreds of millions of cases and continues to circulate globally. To establish a novel SARS-CoV-2 human challenge model that enables controlled investigation of pathogenesis, correlates of protection and efficacy testing of forthcoming interventions, 36 volunteers aged 18–29 years without evidence of previous infection or vaccination were inoculated with 10 TCID50 of a wild-type virus (SARS-CoV-2/human/GBR/484861/2020) intranasally in an open-label, non-randomized study

Studies have found an increased risk for cardiac complications after SARS-CoV-2 infection and mRNA COVID-19 vaccination, but few have compared these risks. Data from 40 health care systems participating in a large network found that the risk for cardiac complications was significantly higher after SARS-CoV-2 infection than after mRNA COVID-19 vaccination for both males and females in all age groups. These findings support continued use of recommended mRNA COVID-19 vaccines among all eligible persons aged =5 years.

In Milan, high wastewater SARS-CoV-2 loads were found when vaccination coverage was high and traditional surveillance indicators suggested limited SARS-CoV-2 prevalence. This result suggests that there was significant circulating virus in the population during this period, including among vaccinated individuals. The SARS-CoV-2 circulation among vaccinated individuals may create modest evolutionary pressure toward resistance to the host’s immune response, making variants with significant transmission advantages more competitive.

With the Omicron variant (B.1.1.529), SARS-CoV-2 infections and hospitalizations reached record levels. Children younger than 5 years may be especially vulnerable because they are not eligible for COVID-19 vaccination. We examined incidence rates and clinical outcomes of Omicron infection before and after Omicron became the predominant variant in the US. Results of this cohort study suggest that the incidence rate of SARS-CoV-2 infection with Omicron variant was 6 to 8 times that of Delta variant in children younger than 5 years, but severe clinical outcomes were less frequent than with Delta variant.

The outbreak of Coronavirus Disease 2019 (COVID-19) at the end of 2019 turned into a global pandemic. To help analyze the spread and evolution of the virus, we collated and analyzed data related to the viral genome, sequence variations, and locations in temporal and spatial distribution from GISAID. Information from the Wikipedia web page and published research papers were categorized and mined to extract epidemiological data, which was then integrated with the public dataset. Genomic and epidemiological data were matched with public information, and the data quality was verified by manual curation.

We estimated vaccine effectiveness (VE) of the BNT162b2 (Pfizer-BioNTech, https://www.pfizer.com) booster dose against SARS-CoV-2 infection and reduction of complications (hospitalization, severe disease, and death) among breakthrough cases in persons in Israel >16 years of age for <20 weeks. VE estimates reached 96.8% (95% CI 96.0%-97.5%) for persons 16-59 years of age and 93.1% (95% CI 91.8%-94.2%) for persons >60 years of age on week 3. VE estimates remained at these levels for 8 weeks in the 16-59 age group and 11 weeks in those >60. A slow decline followed, becoming more pronounced in the last 2-3 weeks of evaluation. Estimates in the last week of evaluation were 77.6% (95% CI 68.4%-84.2%) and 61.3% (52.5%-68.4%) for persons 16-59 years and >60 years.

We report wastewater surveillance for SARS-CoV-2 variants of concern by using mutation-specific, real-time PCR and rapid nanopore sequencing. This surveillance might be useful for an early warning in a scenario in which a new variant is emerging, even in areas that have low virus incidences.

We retrieved 8,837 records from the search strategy; 71 studies (61 clinical and 10 non-clinical studies, involving 17,719,495 pregnant persons and 389 pregnant animals, respectively) were included. Most studies (94%) were conducted in high-income countries and were cohort studies (51%). Less than 15% of studies were classified as high risk of bias. We identified nine COVID-19 vaccine studies, two preclinical studies, and seven involving 309,164 pregnant persons, mostly exposed to mRNA vaccines. Neither pregnancy outcomes nor reactogenicity exceeded the expected rates. The only exception was postpartum hemorrhage after COVID-19 vaccination reported by two studies. In conclusion, we found no safety concerns for currently administered COVID-19 vaccines during pregnancy.

VE against symptomatic infection was considerably lower during Omicron- versus Delta-predominance (70% vs. 95% among =18 year-olds). During Omicron-predominance, estimated 3-dose VE at <4 weeks post-vaccination was highest in 12-17 year-olds (89·7%), followed by =60 year-olds (87·8%) and 18-59 year-olds (77·4%), and declined to 84·4% at 4 to <8 weeks post-vaccination and 51·1% and 76·4% at 8 to <12 weeks post-vaccination, respectively. VE against hospitalization was high in all age groups and remained >90% among =60 year-olds and >75% among 18-59 year-olds at 8 to <12 weeks post-vaccination, while VE against severe illness among =60 year-olds was >95% at 8 to <12 weeks.

As the COVID Human Genetic Effort consortium (https://www.covidhge.com/), we have studied genetic and immunological determinants of life-threatening COVID-19 pneumonia1, multisystem inflammatory syndrome (MIS-C)2, resistance to SARS-CoV-2 infection3 and ‘COVID toes’4, and here we present our efforts to investigate post-acute COVID-19 syndrome, or ‘long COVID’.

Using the Israeli Ministry of Health database, we extracted data on 1,252,331 persons who were 60 years of age or older and eligible for the fourth dose during a period in which the B.1.1.529 (omicron) variant of SARS-CoV-2 was predominant. The number of cases of severe Covid-19 per 100,000 person-days (unadjusted rate) was 1.5 in the aggregated four-dose groups, 3.9 in the three-dose group, and 4.2 in the internal control group. Protection against confirmed infection appeared short-lived, whereas protection against severe illness did not wane during the study period.

We measured neutralization of the Omicron BA.1 variant pseudovirus by post-vaccination serum samples after two and three immunizations with the Pfizer/BioNTech162b2 SARS-CoV-2 mRNA (Pfizer/BNT162b2) vaccine, convalescent serum samples from unvaccinated individuals infected by different variants, and clinical-stage therapeutic antibodies. We found that titers against the Omicron variant were low or undetectable after two immunizations and in many convalescent serum samples, regardless of the infecting variant. A booster vaccination increased titers more than 30-fold against Omicron to values comparable to those seen against the D614G variant after two immunizations.

In this prospective cohort of frontline workers, a third mRNA vaccine dose provided strong (91%) protection against delta infection, similar to the findings of a study showing an effectiveness of 89 to 94% for three doses of mRNA vaccine against medically attended Covid-19 during a period when the delta variant was predominant.4 In contrast, our estimate of vaccine effectiveness of 60% for three doses against omicron infection was lower than the corresponding effectiveness of three doses against medically attended Covid-19 (82 to 90%) in the same study.

Since its emergence in 2019, severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has caused hundreds of millions of cases and continues to circulate globally. To establish a novel SARS-CoV-2 human challenge model that enables controlled investigation of pathogenesis, correlates of protection and efficacy testing of forthcoming interventions, 36 volunteers aged 18–29 years without evidence of previous infection or vaccination were inoculated with 10 TCID50 of a wild-type virus (SARS-CoV-2/human/GBR/484861/2020) intranasally in an open-label, non-randomized study

Studies have found an increased risk for cardiac complications after SARS-CoV-2 infection and mRNA COVID-19 vaccination, but few have compared these risks. Data from 40 health care systems participating in a large network found that the risk for cardiac complications was significantly higher after SARS-CoV-2 infection than after mRNA COVID-19 vaccination for both males and females in all age groups. These findings support continued use of recommended mRNA COVID-19 vaccines among all eligible persons aged =5 years.

In Milan, high wastewater SARS-CoV-2 loads were found when vaccination coverage was high and traditional surveillance indicators suggested limited SARS-CoV-2 prevalence. This result suggests that there was significant circulating virus in the population during this period, including among vaccinated individuals. The SARS-CoV-2 circulation among vaccinated individuals may create modest evolutionary pressure toward resistance to the host’s immune response, making variants with significant transmission advantages more competitive.

With the Omicron variant (B.1.1.529), SARS-CoV-2 infections and hospitalizations reached record levels. Children younger than 5 years may be especially vulnerable because they are not eligible for COVID-19 vaccination. We examined incidence rates and clinical outcomes of Omicron infection before and after Omicron became the predominant variant in the US. Results of this cohort study suggest that the incidence rate of SARS-CoV-2 infection with Omicron variant was 6 to 8 times that of Delta variant in children younger than 5 years, but severe clinical outcomes were less frequent than with Delta variant.

The outbreak of Coronavirus Disease 2019 (COVID-19) at the end of 2019 turned into a global pandemic. To help analyze the spread and evolution of the virus, we collated and analyzed data related to the viral genome, sequence variations, and locations in temporal and spatial distribution from GISAID. Information from the Wikipedia web page and published research papers were categorized and mined to extract epidemiological data, which was then integrated with the public dataset. Genomic and epidemiological data were matched with public information, and the data quality was verified by manual curation.

We estimated vaccine effectiveness (VE) of the BNT162b2 (Pfizer-BioNTech, https://www.pfizer.com) booster dose against SARS-CoV-2 infection and reduction of complications (hospitalization, severe disease, and death) among breakthrough cases in persons in Israel >16 years of age for <20 weeks. VE estimates reached 96.8% (95% CI 96.0%-97.5%) for persons 16-59 years of age and 93.1% (95% CI 91.8%-94.2%) for persons >60 years of age on week 3. VE estimates remained at these levels for 8 weeks in the 16-59 age group and 11 weeks in those >60. A slow decline followed, becoming more pronounced in the last 2-3 weeks of evaluation. Estimates in the last week of evaluation were 77.6% (95% CI 68.4%-84.2%) and 61.3% (52.5%-68.4%) for persons 16-59 years and >60 years.

We report wastewater surveillance for SARS-CoV-2 variants of concern by using mutation-specific, real-time PCR and rapid nanopore sequencing. This surveillance might be useful for an early warning in a scenario in which a new variant is emerging, even in areas that have low virus incidences.

We retrieved 8,837 records from the search strategy; 71 studies (61 clinical and 10 non-clinical studies, involving 17,719,495 pregnant persons and 389 pregnant animals, respectively) were included. Most studies (94%) were conducted in high-income countries and were cohort studies (51%). Less than 15% of studies were classified as high risk of bias. We identified nine COVID-19 vaccine studies, two preclinical studies, and seven involving 309,164 pregnant persons, mostly exposed to mRNA vaccines. Neither pregnancy outcomes nor reactogenicity exceeded the expected rates. The only exception was postpartum hemorrhage after COVID-19 vaccination reported by two studies. In conclusion, we found no safety concerns for currently administered COVID-19 vaccines during pregnancy.

VE against symptomatic infection was considerably lower during Omicron- versus Delta-predominance (70% vs. 95% among =18 year-olds). During Omicron-predominance, estimated 3-dose VE at <4 weeks post-vaccination was highest in 12-17 year-olds (89·7%), followed by =60 year-olds (87·8%) and 18-59 year-olds (77·4%), and declined to 84·4% at 4 to <8 weeks post-vaccination and 51·1% and 76·4% at 8 to <12 weeks post-vaccination, respectively. VE against hospitalization was high in all age groups and remained >90% among =60 year-olds and >75% among 18-59 year-olds at 8 to <12 weeks post-vaccination, while VE against severe illness among =60 year-olds was >95% at 8 to <12 weeks.

As the COVID Human Genetic Effort consortium (https://www.covidhge.com/), we have studied genetic and immunological determinants of life-threatening COVID-19 pneumonia1, multisystem inflammatory syndrome (MIS-C)2, resistance to SARS-CoV-2 infection3 and ‘COVID toes’4, and here we present our efforts to investigate post-acute COVID-19 syndrome, or ‘long COVID’.

Using the Israeli Ministry of Health database, we extracted data on 1,252,331 persons who were 60 years of age or older and eligible for the fourth dose during a period in which the B.1.1.529 (omicron) variant of SARS-CoV-2 was predominant. The number of cases of severe Covid-19 per 100,000 person-days (unadjusted rate) was 1.5 in the aggregated four-dose groups, 3.9 in the three-dose group, and 4.2 in the internal control group. Protection against confirmed infection appeared short-lived, whereas protection against severe illness did not wane during the study period.

We measured neutralization of the Omicron BA.1 variant pseudovirus by post-vaccination serum samples after two and three immunizations with the Pfizer/BioNTech162b2 SARS-CoV-2 mRNA (Pfizer/BNT162b2) vaccine, convalescent serum samples from unvaccinated individuals infected by different variants, and clinical-stage therapeutic antibodies. We found that titers against the Omicron variant were low or undetectable after two immunizations and in many convalescent serum samples, regardless of the infecting variant. A booster vaccination increased titers more than 30-fold against Omicron to values comparable to those seen against the D614G variant after two immunizations.

In this prospective cohort of frontline workers, a third mRNA vaccine dose provided strong (91%) protection against delta infection, similar to the findings of a study showing an effectiveness of 89 to 94% for three doses of mRNA vaccine against medically attended Covid-19 during a period when the delta variant was predominant.4 In contrast, our estimate of vaccine effectiveness of 60% for three doses against omicron infection was lower than the corresponding effectiveness of three doses against medically attended Covid-19 (82 to 90%) in the same study.