Pfizer to test COVID-19 vaccine in larger group of children below 12

By Michael Erman and Ankur Banerjee

(Reuters) – Pfizer Inc said on Tuesday it will begin testing its COVID-19 vaccine in a larger group of children under age 12 after selecting a lower dose of the shot in an earlier stage of the trial.

The study will enroll up to 4,500 children at more than 90 clinical sites in the United States, Finland, Poland and Spain, the company said.

Based on safety, tolerability and the immune response generated by 144 children in a phase I study of the two-dose shot, Pfizer said it will test a dose of 10 micrograms in children between 5 and 11 years of age, and 3 micrograms for the age group of 6 months to 5.

A Pfizer spokesperson said the company expects data from 5- to 11-year-olds in September and would likely ask regulators for emergency use authorization later that month. Data for children 2 to 5 years old could arrive soon after that, he said.

Pfizer expects to have data from the 6-month to 2-year-old age group sometime in October or November.

The vaccine – made by Pfizer and German partner BioNTech SA – has been authorized for use in children as young as 12 in Europe, the United States and Canada. They receive the same dose as adults: 30 micrograms.

Nearly 7 million teens have received at least one dose of the vaccine in the United States, according to the U.S. Centers for Disease Control and Prevention.

Inoculating children and young people is considered a critical step toward reaching “herd immunity” and taming the COVID-19 pandemic.

Still, scientists in the United States and elsewhere are studying the possibility of a link between heart inflammation and mRNA vaccines, particularly in young men. Both Pfizer and Moderna Inc’s vaccines are mRNA shots.

Israel’s Health Ministry said last week it had found the small number of myocarditis cases observed mainly in young men who received the Pfizer vaccine there were probably linked to their vaccination. The cases were generally mild and did not last long.

Pfizer has said it is aware of the Israeli observations of myocarditis and that no causal link to its vaccine has been established.

(Reporting by Ankur Banerjee in Bengaluru and Michael Erman in New York; Editing by Arun Koyyur, Will Dunham and Mark Heinrich)

More unvaccinated U.S. adolescents hospitalized; myocarditis may be rare vaccine side effect in teens

By Nancy Lapid

(Reuters) – The following is a roundup of some of the latest scientific studies on the novel coronavirus and efforts to find treatments and vaccines for COVID-19, the illness caused by the virus.

COVID-19 hospitalizations up among U.S. adolescents

COVID-19 hospitalizations rose among U.S. adolescents in March and April, and nearly a third of those hospitalized needed intensive care, according to data from more than 250 hospitals in 14 states released by the Centers for Disease Control and Prevention (CDC) on Friday. “Rates of COVID-19-associated hospitalization among adolescents also exceeded historical rates of seasonal influenza-associated hospitalization during comparable periods,” researchers reported in the CDC’s Morbidity and Mortality Weekly Report. The hospitals reported a total of 204 adolescents hospitalized for COVID-19 in March and April. “Until they are fully vaccinated, adolescents should continue to wear masks and take precautions when around others who are not vaccinated to protect themselves, and their family, friends, and community,” CDC Director Rochelle Walensky said in a statement on Friday. “I ask parents, relatives and close friends to join me and talk with teens about the importance of these prevention strategies and to encourage them to get vaccinated.”

Heart inflammation may be rare vaccine side effect in teens

Temporary heart inflammation may be a rare side effect of the Pfizer/BioNTech COVID-19 vaccine in teenagers, according to pediatricians who reported on seven cases from across the United States. The previously healthy adolescents – all boys – developed chest pain within four days after their second dose. MRI exams showed myocarditis, or heart muscle inflammation. “Fortunately, none of our patients was critically ill,” the authors reported on Friday in Pediatrics. The boys’ symptoms resolved “rapidly” with medication. Measures of cardiac status had returned to normal at check-ups performed after one-to-three weeks. Myocarditis is a known rare adverse event following other vaccinations, the authors noted. There is no proof, however, that the vaccine caused these cases. “So far, over 2.2 million teenagers (aged) 16-17 have already received 2 doses of Pfizer vaccine, and over 3 million kids 12-15 years old have received dose #1,” said coauthor Dr. Judy Guzman-Cottrill of Oregon Health & Science University. “These are huge, very reassuring denominators.” COVID-19 itself can cause myocarditis, she noted. “After looking at the risks and benefits, the data support getting kids vaccinated.”

Measuring longer-lasting COVID-19 immunity feasible

Along with testing for antibody levels after COVID-19 or vaccination to gauge a person’s immunity to the virus, measuring the response of the immune system’s T cells could provide important information, according to researchers based at Cardiff University. While antibody levels wane over time, T cell responsiveness can last for months or years. But T cells have been harder to measure in cost-effective ways. Adapting a method widely employed to measure immune responses to other types of infections, the researchers took blood samples from adults and children and stimulated T cells with small proteins specific to the SARS-CoV-2 virus. T cells that recognize these proteins, because the person has been previously infected or vaccinated, “are triggered to produce chemicals like interferon which can be easily measured,” said study coauthor Andrew Godkin. The results were about 96% accurate, researchers reported on Tuesday on medRxiv ahead of peer review. “The test is very sensitive and seems to be accurate at identifying people previously exposed to the virus,” Godkin said. “The test is widely available, easy to employ, and should play a very useful role in monitoring this pandemic.”

Virus unlikely to insert genetic fragments into patients’ genetic code

A new study refutes the controversial claim made by researchers last month in PNAS that small fragments of genetic instructions from the coronavirus became integrated into the genome of infected cells, in test tube experiments. In principle, coronavirus RNA generated by such integrated snippets, while probably not harmful, might cause positive COVID-19 PCR tests long after a patient has recovered, the authors of that study said. But when researchers in Australia sought to find signs of SARS-CoV-2 genetic code integrated into the DNA of infected cells, they could not find any. “This was despite using the same sequencing technology and cell type (as in the PNAS study) and performing substantially more DNA sequencing,” said Geoffrey Faulkner of the University of Queensland. The new finding were posted on Sunday on bioRxiv ahead of peer review. The researchers did find copies of hepatitis B virus integrated into liver tissue, and copies of other DNA elements integrated into the cells they experimented with, “suggesting our approach would have found SARS-CoV-2 copies” if they were present, he said. His team agrees with others who suggest the PNAS findings may have reflected unintended effects of experimental methods. “We think SARS-CoV-2 integration into DNA is possible in human cells even if it is likely to be incredibly rare in patients,” Faulkner said.

(Reporting by Nancy Lapid and Christine Soares; Editing by Bill Berkrot)

Post vaccination infection rare but possibly contagious; study refutes another anti-vax pregnancy claim

By Nancy Lapid

(Reuters) – The following is a roundup of some of the latest scientific studies on the novel coronavirus and efforts to find treatments and vaccines for COVID-19, the illness caused by the virus.

Breakthrough infections rare, but potentially contagious

As of April 30, when roughly 101 million Americans had been fully vaccinated against COVID-19, “breakthrough” infections had been reported in 0.01% of them, the U.S. Centers for Disease Control and Prevention (CDC) reported on Tuesday. Roughly 27% of breakthrough infections were asymptomatic, while in 2% of cases, patients died. The CDC had genetic data for virus samples from 555 breakthrough infections. Mutated variants of the coronavirus, including those first seen in the UK and South Africa, accounted for 64% of the breakthroughs. In a separate study posted Tuesday on medRxiv ahead of peer review, researchers reported that among 20 fully-vaccinated healthcare workers with breakthrough COVID-19 cases, all were infected with variants. An earlier study had linked breakthrough infections with low viral loads, suggesting low transmission risks, but “we found many samples in our breakthrough cohort with high viral load,” said coauthor Pavitra Roychoudhury of the University of Washington. “Our work suggests that not all breakthrough infections are at low risk of initiating transmission and, if they did, these infections could lead to the continued spread of variants of concern, particularly in areas with low vaccination rates.”

Study refutes anti-vaxxers’ pregnancy, breast milk claims

Unfounded claims by anti-vaccine activists that COVID-19 shots from Pfizer/BioNTech and Moderna will damage the placenta and contaminate breast milk have been refuted by new data. The vaccines deliver synthetic messenger RNA (mRNA), which instructs the body to make proteins that in turn induce antibodies to attack the coronavirus. Anti-vaxxers claim, with no evidence, that mRNA also induces antibodies that attack a protein called syncytin-1, which is important for the developing placenta during pregnancy. They also claim mRNA from the vaccines ends up in breast milk. When researchers studied blood samples from 15 women who received at least one dose of the Pfizer/BioNTech vaccine – including two pregnant women and five who were breastfeeding – they saw coronavirus antibodies but no antibodies against syncytin-1. None of the breastfeeding women had vaccine mRNA in their milk, according to a report posted Tuesday on medRxiv ahead of peer review. “This small study tells us that it is unlikely that COVID-19 mRNA vaccination will cause complications in pregnancy or fertility through cross-reacting antibodies against syncytin-1, or for breastfed infants through breast milk,” the authors said.

Vaccines appear safe for “long COVID” survivors

COVID-19 survivors with lingering symptoms can safely be vaccinated against the coronavirus, a small study suggests. Researchers tracked 36 individuals with “long COVID” who had been hospitalized while acutely ill and who later received at least one dose of either the Pfizer/BioNTech or AstraZeneca vaccine. Eight months after admission to the hospital, and before vaccination, participants had at least one lingering symptom and half had at least four symptoms. Before vaccination, their quality-of-life was “markedly reduced” from normal, the researchers reported on Monday in Annals of Internal Medicine. One month after vaccination, 71% of their symptoms remained unchanged, 23% of their symptoms were improved, and 6% of symptoms had worsened. There was no significant worsening in quality-of-life or mental well-being, and outcomes were similar with both vaccines, researchers reported. The results may reassure people with persistent COVID-19 symptoms that the different types of vaccines developed by Pfizer/BioNTech or AstraZeneca are “not associated with a decrease in quality of life or worsening of symptoms,” the researchers said.

Moderna says vaccine safe, effective in adolescents

Moderna’s COVID-19 vaccine was 100% effective in a trial involving 3,732 adolescents aged 12-17, with no major safety problems, the company said on Tuesday. Among participants who received two doses, there were no cases of COVID-19 compared with four cases among those who received a placebo. After only one dose, the vaccine was 93% effective in this age group, Moderna said. Side effects were similar to those reported in earlier studies, including headache, fatigue, body aches and chills. Moderna plans to submit the findings to regulators for emergency use authorization in June. The U.S. Centers for Disease Control and Prevention (CDC) said on Monday it is monitoring rare reports of mild heart inflammation after COVID-19 vaccination in adolescents. The CDC said the condition is not occurring at higher rates than would be expected in the general population, so no causal link to the vaccine has been established. Dr. Amesh Adalja of the Johns Hopkins Center for Health Security said even if vaccines turn out to be the cause, it is important to consider the risk-benefit ratio. “Vaccines are going to unequivocally be much more beneficial,” outweighing any low risk of myocarditis, he said.

(Reporting by Nancy Lapid, Julie Steenhuysen and Radhika Anilkumar; Editing by Bill Berkrot)