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One in three unvaccinated COVID-19 survivors in a Spanish cohort had no detectable SARS-CoV-2 antibodies nearly 1 year after infection, according to a prospective study published today in BMC Medicine.
A team led by researchers from the Barcelona Institute for Global Health (ISGLOBAL) measured SARS-CoV-2 antibody levels in 1,076 adults aged 43 to 72 years from June to November 2020 and again from May to July 2021, before the emergence of the Omicron variant. Participants also completed questionnaires on lifestyle, health-related, and sociodemographic characteristics.
By the end of the study, 12.1% of participants were unvaccinated, 24.8% were partially vaccinated, and 63.1% were fully vaccinated. Median time since the last dose was 28 days. More unvaccinated participants had a previous COVID-19 diagnosis (32.3%) or positive antibody test in 2020 (49.2%) than vaccinated participants (12.5% and 28.2%, respectively).
During the second antibody measurement more than 300 days after primary COVID-19 infection, 67.2% of infected unvaccinated participants still had antibodies, while serologic status was undetermined in 15.5%, and 20.3% had no antibodies. Those with antibodies were more likely to have had an asymptomatic infection (61.9% vs 25.6%), be older than 60 years (42.8% vs 34.8%), and smoke (19% vs 4.6%).
Nearly all vaccinated participants had antibodies (99.3% of the fully and 94.4% of partially vaccinated). Among COVID-19 survivors, vaccination improved the immune response, particularly the second dose. Vaccinated infected participants had higher antibody concentrations over time than their never-infected vaccinated counterparts.
mRNA vaccines, particularly Moderna’s version, triggered greater antibody levels after two doses than the AstraZeneca/Oxford and Johnson & Johnson versions. Multivariable regression analyses showed that immune responses varied by type of vaccine, time since infection, sex, smoking status, and the presence of mental and cardiovascular illnesses.
“Our data underscore the importance of vaccinating people even if they have been previously infected, and confirm that hybrid immunity is superior and more durable,” first author Marianna Karachaliou, PhD, said in an ISGLOBAL news release.
Sep 16 BMC Med study
Sep 15 ISGLOBAL news release
Ghana’s Ministry of Health today declared an end to its first-ever Marburg virus disease outbreak after officials confirmed three cases, two of them fatal, the World Health Organization (WHO) said in an update.
The outbreak is considered to be over after 42 days, or two incubation periods, have passed since the last known case. The incubation period is the time between infection and the onset of symptoms.
Officials first declared the outbreak on Jul 7 after they confirmed Marburg virus in the Ashanti, Savannah, and Western regions. They followed up with 198 contacts for 42 days of observation. In cooperation with the WHO, they rolled out outbreak control measures after the first case was identified, stepping up disease surveillance, testing, contact-tracing, clinical care, and awareness-raising.
Marburg is a highly infectious disease in the same family as Ebola and has a high case-fatality rate of 24% to 88%. Previous reports of the Ghana outbreak noted four cases and three deaths, but one of those fatal cases was later ruled out.
“Marburg is a frightening disease, as it is highly infectious and lethal. There are no vaccines or antiviral treatments. Any outbreak of Marburg is a major concern,” said WHO Regional Director for Africa Matshidiso Moeti, MBBS.
The Marburg outbreak in Ghana was the second of its kind in West Africa. Guinea reported a single case in an outbreak that was declared over a year ago. Previous African outbreaks and cases have been reported in Angola, the Democratic Republic of the Congo (DRC), Kenya, South Africa, and Uganda.
Sep 16 WHO notice
In addition to detailing the recent New York polio case, the Global Polio Eradication Initiative (GPEI) in its weekly update yesterday noted 4 circulating vaccine-derived type 1 (cVDPV1) cases and 28 vaccine-derived type 2 (cVDPV2) cases in the DRC and 8 cVDPV2 cases in Yemen.
The 4 cVDPV1 cases in the DRC were in Haut-Lomami province and are the first to be confirmed in the country. The 28 cVDPV2 cases were in Bas-Uele and Maniema provinces (1 each), South Kivu (2), and Tanganyika (24), and they bring the number of cases in 2022 to 110. The country had 28 cVDPV2 cases in 2021.
Of Yemen’s 8 cVDPV2 cases, 2 were in Al Mahwit city, 1 each in Ibb and Sa’dah governorates, and 4 in Sana’a governorate. The country has now reached 127 cVDPV2 cases for 2022 after recording 66 cVDPV2 cases and 3 cVDPV1 cases in 2021.
In officially confirming the New York polio case, which is the first US case in years, the GPEI said, “It is important to note that since initial isolation of VDPV2, local and national public health authorities have already been operating on the assumption that this strain is circulating, and as such, this official classification at this time does not affect the operational response.”
Sep 15 GPEI update
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