Fierce Healthcare's Fierce 15 of 2024

New Vaccine Vital To Protect Against Mutated Delta Variants

Researchers in Japan are calling for new vaccines to be developed to protect the public from breakthrough variants of the novel coronavirus, such as the highly contagious Delta strain that comes with a combination of mutations.

A team led by Hisashi Arase, a professor of immunochemistry at Osaka University's Research Institute for Microbial Diseases, issued a paper on its research findings that can be viewed by accessing (https://www.Biorxiv.Org/content/10.1101/2021.08.22.457114v1.Full#ref-44).

It said mRNA-based vaccines, such as the one developed by Pfizer Inc., provide effective protection against most common COVID-19 variants, but "identifying likely breakthrough variants is critical for future vaccine development."

The group ascertained that when four specific mutations are added to the Delta variant, the effectiveness of current vaccines could be greatly weakened.

The members first analyzed blood samples taken from 20 people who had received Pfizer vaccine jabs to gauge the ability of their immune systems to fight off infection. They confirmed that the vaccine is effective in preventing infection through the Delta variant.

But the researchers discovered that the vaccine's effectiveness against the Delta variant has decreased in comparison with its effectiveness against other existing strains.

They also found that some antibodies created by the vaccine do not attach themselves to the Delta variant.

A key mechanism in preventing infection requires antibodies created by a vaccine to attach to the protein of a virus. If this does not happen, the effectiveness of the antibodies noticeably drops.

They also studied changes in the effectiveness of antibodies when the Delta variant further mutates. To accomplish this, they created an artificial non-pathogenic virus for laboratory use and chose four mutations that potentially derive from the Delta variant, based on mutations already detected.

When a mutation was added to the Delta variant one at a time, the effectiveness to prevent infection remained intact.

But when all four mutations were added at once, many antibodies did not attach to the virus, meaning effectiveness was substantially reduced.

Team members found that creating an antibody based on the Delta variant, rather than on conventional variants, can help protect against the Delta variant with four mutations added.

A variant that contains two of the four mutations has already been found, the researchers said.

The chances of the virus mutating rises exponentially with increased rates of infections, they added.

"It is clearly necessary to find a new strategy to develop a new vaccine," Arase said.

COVID-19 Vaccine Confers Protection Against Post-COVID-19 Conditions

Among people with mild COVID-19 infection during Delta- and Omicron-predominant eras, vaccination protected against the development of post-COVID conditions, according to study findings published in The Journal of Infectious Diseases.

Researchers conducted a retrospective case-control analysis of a longitudinal cohort study (HEROES-RECOVER) to determine whether COVID-19 vaccination was protective against the development of post-COVID conditions among individuals with mild infections during the Delta- and Omicron-dominant eras.

Health care workers, first responders, and other essential workers in the United States aged 18 years and older who had reverse transcriptase-polymerase chain reaction (RT-PCR)-confirmed SARS-CoV-2 infections between June 2021 and September 2022 were eligible for inclusion. Participants were surveyed for post-COVID conditions, which was defined as symptoms lasting longer than 1 month beyond the initial infection.

The primary outcome was post-COVID conditions, which was defined as self-reported symptoms lasting at least 4 weeks after acute infection. To compare the odds of post-COVID conditions among vaccinated (2 or 3 doses of monovalent mRNA COVID-19 vaccine) vs unvaccinated individuals, logistic regression was used.  

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Further research is needed to evaluate whether this effect is even greater with additional vaccine doses and the improved variant-vaccine match of updated COVID-19 vaccines.

A total of 936 participants (mean age, 44.2 years; women, 61.0%; White, 88.2%; non-Hispanic, 43.4%) were included in the final analysis. Overall, 779 (83.2%) participants received 2 doses of the mRNA COVID-19 vaccine at least 2 weeks prior to infection, of whom 478 (51.1%) also received a third vaccine dose at least 1 week prior to the infection.

At least 1 post-COVID condition symptom was reported by 215 (23.3%) participants, with 152 (16.5%) participants reporting at least 2 symptoms. The most frequently reported category of symptoms was general symptoms, including pain/fatigue (16.2%), followed by neurologic (13.7%), cardiovascular/respiratory (11.4%), and other (8.5%) symptoms.

In the adjusted analysis, participants who received a 3rd vs no dose of COVID-19 vaccine had lower odd of the following post-COVID conditions:

Gastrointestinal symptoms (adjusted odds ratio [aOR], 0.37; 95% CI, 0.16-0.85);

Neurologic symptoms (aOR, 0.56; 95% CI, 0.32-0.97); and

Other symptoms (aOR, 0.48; 95% CI, 0.25-0.91).

No associations of significance were observed between 3 doses of COVID-19 vaccine and the likelihood of number of symptoms, cardiovascular/respiratory symptoms, and general symptoms.

The odds of post-COVID conditions with at least 1 symptom when comparing unvaccinated participants with those who received 2 doses of COVID-19 vaccine at least 14 days prior to acute infection was 0.84 (95% CI, 0.53-1.25).

Study limitations include the exclusion of participants without SARS-CoV-2 infection, potential recall bias and unmeasured confounding, and reduced generalizability of results to older and less healthy individuals.

"Further research is needed to evaluate whether this effect is even greater with additional vaccine doses and the improved variant-vaccine match of updated COVID-19 vaccines," the researchers concluded.

Disclosure: Some of the study authors declared affiliations with biotech, pharmaceutical, and/or device companies. Please see the original reference for a full list of authors' disclosures.

This article originally appeared on Infectious Disease Advisor

Israel Becomes First Country To Offer A 3rd COVID Vaccine Dose

(JTA) — Israel has begun inviting immunocompromised adults to receive a third dose of the COVID-19 vaccine, as case rates in the country have risen again due to the spread of the Delta variant.

Israel led the world in vaccinating most of its population early this year, and the country fully reopened as COVID cases plummeted to a low of single digits during a few days in late May and early June. But cases have since spiked back up to more than 400 per day.

In response, Israel is the first country in the world to approve a third dose of the vaccine as a booster shot, according to The Times of Israel. Last week, Pfizer asked countries to approve a booster dose for those who have received a vaccine.

On the heels of the approval of the booster shot, the Tel Aviv-area Sheba Medical Center, Israel's largest hospital, invited recipients of heart transplants to get a booster shot.

A majority of Israelis are vaccinated. In addition to authorizing the booster shot, Israel also brought back an indoor mask mandate in an effort to curb rising infections.

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