Will COVID-19 Vaccines Need to be Adapted Regularly?

Influenza vaccines need to be evaluated every year to ensure they remain effective against new influenza viruses. Will the same apply to COVID-19 vaccines? In order to gauge whether and to what extent this may be necessary, a team of researchers from Charité – Universitätsmedizin Berlin compared the evolution of endemic ‘common cold’ coronaviruses with that of influenza viruses. The researchers predict that, while the pandemic is ongoing, vaccines will need to undergo regular updates. A few years into the post-pandemic period, however, vaccines are likely to remain effective for longer. This study has been published in Virus Evolution.

Influenza viruses are masters at evading the human immune system. They undergo such rapid changes that antibodies produced by the immune system in response to a previous infection or vaccination become unable to neutralize them. This is why the complex task of evaluating and updating the seasonal influenza vaccine has to be repeated every year. Mutations within SARS-CoV-2 have already produced a number of variants, some of which (such as the South African variant) partially evade the body’s immune response. As a result, some vaccine manufacturers have already started to develop new versions of their vaccines. What does this mean for the future? Will COVID-19 vaccines mirror influenza vaccines in requiring regular updates?

In order to gauge whether, over the long term, SARS-CoV-2 is likely to demonstrate an immune evasion capability on par with that of influenza viruses, Charité virologists have studied the genetic evolution of the four currently known ‘common cold’ coronaviruses. These relatively harmless coronaviruses are known to be responsible for approximately 10 percent of common colds in the world and have been in circulation in humans significantly longer than SARS-CoV-2. Just like SARS-CoV-2, they enter human cells using the ‘spike protein’, a surface protein which gives the virus its characteristic crown-like appearance (and name). The spike protein also forms the target of all current COVID-19 vaccines.

For their study, the researchers focused on the two longest-known coronaviruses (termed 229E and OC43), tracing changes in the spike gene approximately 40 years into the past. The researchers started by comparing sequences from a range of old samples which had been deposited in a genetic sequence data bank. Based on the mutations which had emerged over time, they then produced phylogenetic trees for both coronaviruses. The researchers compared their findings with the phylogenetic tree of H3N2, an influenza subtype which is particularly effective at evading the human immune response.

The researchers’ calculations revealed one feature which was common to the phylogenetic reconstructions of both the coronaviruses and the influenza virus: all three had a pronounced ladder-like shape. “An asymmetrical tree of this kind likely results from the repeated replacement of one circulating virus variant by another which carried a fitness advantage,” explains the study’s first author, Dr. Wendy K. Jó from Charité’s Institute of Virology. “This is evidence of ‘antigenic drift’, a continuous process involving changes to surface structures which enable viruses to evade the human immune response. It means that these endemic coronaviruses also evade the immune system, just like the influenza virus. However, one also has to look at the speed with which this evolutionary adaptation happens.”

For this step, the researchers determined the three viruses’ evolutionary rates. While the influenza virus accumulated 25 mutations per 10,000 nucleotides (genetic building blocks) per year, the coronaviruses accumulated approximately 6 such mutations in the same timeframe. The rate of change of the endemic coronaviruses was therefore four times slower than that of the influenza virus. “As far as SARS-CoV-2 is concerned, this is good news,” summarizes Prof. Dr. Christian Drosten, Director of the Institute of Virology and a researcher at the German Center for Infection Research (DZIF).

SARS-CoV-2 is currently estimated to change at a rate of approximately 10 mutations per 10,000 nucleotides per year, meaning the speed at which it evolves is substantially higher than that of the endemic coronaviruses. “This rapid genetic change in SARS-CoV-2 is reflected in the emergence of numerous virus variants across the globe,” explains study lead Prof. Dr. Jan Felix Drexler, a researcher at both the Institute of Virology and the DZIF. “This, however, is likely due to the high rates of infection seen during the pandemic. When infection numbers are so high, a virus is able to evolve more rapidly. Based on the rates of evolution seen in the endemic common cold coronaviruses, we expect that SARS-CoV-2 will start to change more slowly once infections start to die down – meaning once a large proportion of the global population has developed immunity either as a result of infection or through vaccination. We expect therefore that COVID-19 vaccines will need to be monitored regularly throughout the pandemic and updated where necessary. Once the situation has stabilized, vaccines are likely to remain effective for longer.”

Source: Charité – Universitätsmedizin Berlin

In Pictures: Food of Yat Lok Restaurant (一樂燒鵝) in Central, Hong Kong

Roasted Meats, Noodles and Rice Dishes

The 2021 Michelin 1-star Restaurant

U.S. FDA Clamping Down on Abuse of an OTC Decongestant

Robert Preidt wrote . . . . . . . . .

Makers of inhalers that contain the nasal decongestant propylhexedrine should make design changes to prevent misuse, the U.S. Food and Drug Administration says.

Propylhexedrine is a nasal decongestant in over-the-counter inhalers, and right now is “only marketed under the brand name Benzedrex,” the FDA said. The agency said that propylhexedrine is effective and safe when used for short periods as directed for relief of congestion due to colds, hay fever or other upper respiratory allergies. But misuse can bring dangers.

“Benzedrex inhalers can be legally purchased, but propylhexedrine abuse occurs as people try to find legal ways to get high or increase productivity and concentration,” according to the National Capital Poison Center (NCPC).

“There have been many reports of toxicity associated with propylhexedrine extracted from an inhaler and swallowed or injected. Swallowing the contents of one propylhexedrine inhaler has caused heart attack and lung injury in adults and children,” the NCPC added.

The FDA warns that reports of abuse and misuse of propylhexedrine have been on the rise. The drug can lead to serious problems — including fast or abnormal heart rhythm, high blood pressure and paranoia — that can result in hospitalization, disability or death.

“We are requesting that all manufacturers of [over-the-counter] propylhexedrine nasal decongestant inhalers consider product design changes that support its safe use,” the FDA said in a news release.

“For example, modifying the product to create a physical barrier that would make tampering with the device and abusing the propylhexedrine inside more difficult,” the agency said.

Reducing the amount of propylhexedrine in inhalers could also lower the risk of serious side effects, the FDA noted.

“We continue to evaluate this safety issue and will determine if additional FDA actions are needed,” the agency said.

Propylhexedrine was developed over 60 years ago as a substitute for amphetamine, once the active ingredient in Benzedrex inhalers, according to the NCPC. The center noted that the change was made in response to abuse and deaths from amphetamine extracted from the inhalers.

Propylhexedrine reduces swelling and inflammation of the nasal lining. The recommended dose for adults and kids over 6 is two puffs in each nostril, not more often than every two hours. It shouldn’t be used for more than three days at a time.

Prolonged use may cause congestion to recur or worsen.

The FDA urged people in the U.S. to call 911 or poison control at 800-222-1222 if someone using propylhexedrine experiences severe anxiety or agitation, confusion, hallucinations or paranoia, rapid heartbeat or abnormal heart rhythm, chest pain or tightness.

If you have questions about the drug, including how to use it or whether it may interact with another medicine you take, talk to a pharmacist or your health care provider, the FDA urged.

Source: HealthDay

Char Siu Noodle Soup

Ingredients

4 dried Chinese mushrooms
7 oz barbecue pork (char siu)
1/3 cup fresh or canned bamboo shoots, rinsed and drained
2 cups green vegetable, such as spinach, bok choy or Chinese (Napa) cabbage
2 scallions
14 oz fresh or 11 oz dried egg noodles
4 cups chicken stock
2-3 tablespoons oil
1 teaspoon salt
1/2 teaspoon sugar
1 tablespoon light soy sauce
1 teaspoon Shaoxing rice wine
1/4 teaspoon sesame oil

Method

  1. Soak the dried mushrooms in boiling water for 30 minutes, then drain and squeeze out any excess water. Remove and discard the stems and shred the caps.
  2. Thinly shred the pork, bamboo shoots, green vegetable and scallions.
  3. Cook the noodles in a saucepan of salted boiling water for 2-3 minutes if fresh and 10 minutes if dried, then drain and place in 4 bowls.
  4. Bring the stock to a boil, then reduce the heat to simmering.
  5. Heat a wok over high heat, add the oil and heat until very hot. Stir-fry the pork and half the scallions for 1 minute, then add the mushrooms, bamboo shoots and green vegetable and stir-fry for 1 minute.
  6. Add the salt, sugar, soy sauce, rice wine and sesame oil and blend well.
  7. Pour the stock over the noodles and top with the meat mixture and the remaining scallions.

Makes 4 servings.

Source: The Food of China


Today’s Comic

Meat Consumption Continues to Decline, Now Averaging 57.3 Kg Per Person in Germany

According to provisional data from Germany’s Federal Agricultural Information Centre (BZL), the per capita consumption of animal meat last year was lower than at any time since consumption was first calculated in 1989, at 57.3 kilograms per person – meaning an average of 750 grams less than was consumed in Germany than in the previous year.

Compared to 2019, 2.4 percent less pork and 2.7 percent less beef and veal was produced in 2020. However, the data also showed that net production of poultry meat increased by 1.7 percent, highlighting the urgent need for plant-based chicken producers such as fast-growing vegan fried chicken brand VFC, which is currently expanding its operations from the UK into mainland Europe including Germany.

The governmental report also showed that the transportation of live animals also decreased in 2020: in comparison to 2019, 14.8 per cent fewer live animals were imported and eleven per cent fewer were eleven percent less exported. Furthermore, imports and exports of meat products and canned food decreased by 7.8 percent and 6.5 percent respectively.

Such findings corroborate a study as reported by vegconomist last November which revealed that the number of vegans had doubled from 1.3 million in 2016 to 2.6 million in 2020 — a total of 3.2 percent of the population.

More than 40% of Germans are cutting down on meat, Psychologist Christopher Bryant of Bath University commented: “The social implications here are potentially quite profound. The view that being a carnivore is ‘normal’ is part of the lay moral reasoning for continuing to eat meat. But once that is a minority view, and meat replacement options become cheaper and tastier, the trend is likely to continue in one direction.”

Source: Vegconomist