A study yesterday in JAMA Network Open based on outcomes seen among Singaporean children ages 4 years and younger showed good protection for two doses of monovalent mRNA COVID vaccines during an Omicron surge.

The authors said the findings support vaccinating this age-group, despite low incidence of severe disease or hospitalization.

The study was conducted from October 1, 2022, to March 31, 2023, after all Singaporean children ages 1 to 4 had been vaccinated with mRNA two-dose vaccines in a community vaccination campaign following approval of vaccines for this age-group in August 2022.

The 6-month study period coincided with an Omicron XBB surge in Singapore, during which schools remained open, mask wearing was optional, and close contacts of COVID-19 cases were allowed to remain in school if well.

63% to 75% effective in preventing infections

A total of 121,628 children (median age, 3.1 years) were included in the study, contributing 21,015 ,956 person-days of observation. A total of 45,693 children (37.6%) had a prior SARS-CoV-2 infection, with most having had prior infection during the earlier Omicron BA.1/2 wave, the authors said.

In kids with no previous COVID-19, vaccination was 63.3% effective in protecting against infection. Protection was higher, 74.6%, in those with a documented prior infection. Data were insufficient to assess vaccine effectiveness in fully vaccinated children with prior SARS-CoV-2 infection, the authors said.

There were no hospitalizations among fully vaccinated children, and no deaths were reported during the study.

Rapid increases in pediatric COVID-19 infections coinciding with periods of high community transmission may still place health care systems under strain.

Though vaccinating children under the age of 5 is debatable, the authors said, "Rapid increases in pediatric COVID-19 infections coinciding with periods of high community transmission may still place health care systems under strain."

From 2018 to 2022, more Americans aged 51 to 60 years filed private health insurance claims for Lyme disease than any other age-group, according to a new infographic from the nonprofit FAIR Health.

The 51-to-60 age-group made up 23.5% of Lyme disease claims, followed by those aged 41 to 50 (18.8%), 31 to 40 (14.1%), 19 to 30 (14.0%), 61 to 70 (13.9%), 0 to 18 (11.3%), and older than 70 (4.3%).

Caused by Borrelia burgdorferi bacteria, Lyme disease is spread through the bite of blacklegged (deer) ticks. Symptoms. typically include fever, headache, fatigue, and a characteristic "bull's eye" skin rash. If untreated, joint, cardiac, and neurologic complications may ensue.

The Centers for Disease Control and Prevention estimates that roughly 476,000 Americans are diagnosed and treated for Lyme disease each year, but it cautions that the number is probably an overestimate because some patients are treated presumptively in clinical practice.

Other key findings

The infographic's other results include:

• In 2018, the top five states generating Lyme disease claims, in descending order, were New Jersey, North Carolina, Rhode Island, Connecticut, and Massachusetts. By 2022, the top state was still New Jersey, followed by Vermont, Connecticut, Pennsylvania, and Rhode Island.
• Lyme disease claims were more common in rural than urban areas in June and July, but the opposite was true from November to April.
• Except for the older-than-80 age-group, malaise and soft tissue-related diagnoses were more common among Lyme disease patients than other patients.

"Lyme disease remains a pressing public health concern," FAIR Health President Robin Gelburd, JD, said.

As part of an ongoing rise in detections this month, Colorado and North Dakota reported the reappearance of highly pathogenic avian flu in poultry, the US Department of Agriculture (USDA) Animal and Plant Health Inspection Service (APHIS) said in its latest updates.

Both events involved backyard poultry, but a few other states have reported recent outbreaks on commercial farms. Colorado’s outbreak occurred in Weld County at a location housing 30 birds.

In North Dakota, the virus struck a 10-bird flock in Williams County. State animal health officials in a statement said though detections in wild birds have declined, the virus continues to be a source of disease among domestic birds.

Condor vaccination results

In other US developments, the US Fish and Wildlife Service yesterday reported early findings on a highly pathogenic avian influenza vaccine trial in endangered California condors, following an outbreak in the spring.

Following two doses, 60% had an antibody response expected to provide partial protection against death, and 10% had titers expected to protect fully against death. Results are pending on the one-dose and control groups.

Officials said that, based on the findings, 14 more condors that are slated for release will receive the two-dose series.

H5N1 outbreaks in two European countries

Elsewhere, Norway and Poland reported H5N1 outbreaks in poultry, both in backyard flocks, according to notifications from the World Organization for Animal Health (WOAH).

Poland’s outbreak, its first since July, occurred at a location that has 80 birds in West Pomerania province in the country’s northwest. Norway’s outbreak, its first since February, involved a location with 19 birds in Trogs og Finnmark County in the far north.