A review and meta-analysis of long-term cardiac complications of long COVID finds a high prevalence of chest pain and abnormal heart rhythms (arrythmias).

For the study, published this week in BMC Medicine, a University of Washington–led team reviewed 150 studies on 57 cardiac complications that persisted for at least 1 month after COVID-19 infection. They also conducted a meta-analysis of 137 studies on 17 complications. The studies were published from January 2020 to July 2023.

"Prior reviews synthesized findings of studies on long-term cardiac complications of COVID-19," the researchers wrote. "However, the reporting and methodological quality of these studies has not been systematically evaluated."

Chest pain in 10%, arrhythmias in 8%

Slightly over one quarter (25.3%) of studies were high-quality, according to a customized Newcastle-Ottawa scale. The most widely examined cardiac complications were chest pain and arrhythmias. When study quality and characteristics were disregarded, the estimated prevalence of chest pain and arrhythmias were 9.8% and 8.2%, respectively.

Less-examined complications were stroke (0.5%), heart abnormalities (10.5%), thromboembolism (1.4%), high blood pressure (4.9%), heart failure (1.2%), myocardial injury (1.3%), myocarditis (0.6%), abnormal ventricular function (6.7%), edema (2.1%), coronary disease (0.4%), ischemic heart disease (1.4%), valve abnormalities (2.9%), pericardial effusion (0.8%), atrial fibrillation (2.6%), and impaired diastolic function (4.9%). 

We found there were diverse manifestations of cardiac complications, and many can last for months and even years.

But stratified analyses found that low-quality studies with small sample sizes, unsystematic sampling methods, and cross-sectional designs were more likely to report higher complication rates. For instance, rates of chest pain were 22.2%, 11.1%, and 3.9% in low-, medium-, and high-quality studies. Similar trends were seen for arrhythmias and other less-examined cardiac complications.

"We found there were diverse manifestations of cardiac complications, and many can last for months and even years," the study authors wrote. "Reported findings from previous studies are strongly related to study quality, sample sizes, sampling methods, and designs, underscoring the need for high-quality epidemiologic studies to characterize these complications and understand their etiology."

As highly pathogenic avian flu outbreaks continue at a steady pace, the virus has turned up at another large egg producer, this time in at a facility in Iowa's Sioux County that houses 1.6 million layers, according to the latest updates from the US Department of Agriculture (USDA) Animal and Plant Health Inspection Service (APHIS). The event adds to other recent outbreaks at egg producers, including another in Iowa that had 1.2 million birds, a facility in Ohio that housed 1.3 million birds, and one in Minnesota that led to the loss of nearly 1 million birds.

The surge in H5N1 avian flu activity, which began in early October, has also hit turkey farms hard, as well as other commercial operations. In its latest updates, APHIS also reported outbreaks affecting poultry flocks in seven other states, several of them at commercial farms. They include a broiler farm in Arkansas and turkey producers in Minnesota, North Dakota, and South Dakota. Detections were also reported in backyard flocks in Colorado, Iowa, Nebraska, and Washington state.

Since the outbreaks began in early 2022, they have led to the loss of a record 67.8 million birds. In November alone, the outbreaks have affected 7.6 million poultry.

In related developments, APHIS also reported more than 150 H5N1 detections in wild birds over the past several days, mostly in hunter-harvested waterfowl as part of disease surveillance. Some of the reports also involve birds found dead, including geese, waterbirds, and birds of prey.

Developments overseas

Other countries are also reporting the reappearance of the virus, including Israel, where H5N1 struck a turkey farm in Zora that has 10,500 birds, according to a notification from the World Organization for Animal Health (WOAH). Germany reported an outbreak at a commercial farm in Lower Saxony state, and the United Kingdom has reported recent outbreaks at commercial farms in Devon and Northumberland.

Emerging Infectious Diseases this week published details on five initial cases of clade 1 mpox virus identified in the Democratic Republic of the Congo (DRC). The DRC is currently battling a large outbreak of clade 1 mpox, the first clade 1 outbreak linked to sexual transmission.

In March of 2023, a man from the DRC (case patient 1) in his late 20s reported having two sexual encounters with a man in Europe (suspected primary case) 1 week before returning to the DRC. The DRC man then reported having sexual contact with 9 more people, 6 men and 3 women, the authors said.

After case patient 1 developed penile lesions and fever and was seen in a health clinic, health officials contacted the 9 sexual contacts.

"We performed viral genome sequencing on PCR-positive samples; phylogenetic analysis showed tight clustering among 3 positive samples, suggesting they belong to the same chain of transmission. The closest related sequence beyond this cluster was a 2022 clade I MPXV [mpox virus] sequence from DRC," the authors wrote.

No secondary contacts developed mpox

The 3 positive cases found from testing and the initial 2 cases were all given supportive care and pain control as outpatients. An additional 120 contacts from the 5 cases were monitored over the next 3 weeks. Contacts included sexual partners (5), family members (45), and people who had close nonsexual contact (70). None of these contacts developed clinical symptoms of mpox over the 21-day monitoring period.

Our findings highlight historically unrecognized MPXV transmission through sexual contact and indicate the need for increased routine screening.

"Our findings highlight historically unrecognized MPXV transmission through sexual contact and indicate the need for increased routine screening in sexual health clinics in mpox-endemic and nonendemic regions," the authors concluded.

In 2022, a global sexually transmitted outbreak of clade 2 mpox was identified first in Europe. So far more than 90,000 people, mostly men who have sex with men, have been infected in that outbreak. That outbreak has caused very few fatalities, but the current DRC outbreak has already claimed 581 lives, officials from the World Health Organization confirmed earlier this week.

The UK Veterinary Medicines Directorate and the UK Health Security Agency published their third report on One Health, covering antibiotic use, sales, and antimicrobial resistance during 2019 and finding that a total of 706 tons of antibiotics were consumed by people and animals in the country.

Of note, the use of critically important antimicrobials decreased by 75%, and overall use decreased by 28%, since 2014.

Sixty-eight percent of antibiotics were consumed by people, and 32% by animals in 2019. Food-producing animals saw a 52% decrease in antibiotic consumption between 2014 and 2019, whereas people had an 18% decrease.

The report also focused on resistance in key bacteria, including Salmonella, E coli, and Campylobacter.

Strong human-animal connections

Antimicrobial resistance (AMR) in certain pathogens showed strong connections between people and animals, notably chickens.

Similar patterns of AMR in Campylobacter spp. are reported across chickens, chicken meat, and human patients, suggesting strong linkages through the food chain.

"Similar patterns of AMR in Campylobacter spp. are reported across chickens, chicken meat, and human patients, suggesting strong linkages through the food chain," the report read. "High levels of fluoroquinolone resistance (>40%) have persisted across the sectors despite very low usage of these antibiotics in chickens."

In 2019, resistance in human isolates to ciprofloxacin, an antibiotic used to fight Campylobacter species, was 47.1%, and in retail chickens it was 51% in 2018 and 2019.

Also noted in the report is AMR trends in pets, including cats and dogs. Though antibiotic sales data indicates that, from 2014 to 2019, overall use of antibiotics for both animals decreased, cats were still accounted for high rates of critically important antimicrobials.