{"id":5746,"date":"2020-10-16T11:40:46","date_gmt":"2020-10-16T06:10:46","guid":{"rendered":"http:\/\/www.mymedicplus.com\/news\/?p=5746"},"modified":"2022-03-12T14:58:13","modified_gmt":"2022-03-12T09:28:13","slug":"how-anti-ageing-drugs-could-boost-covid-vaccines-in-older-people","status":"publish","type":"post","link":"https:\/\/www.mymedicplus.com\/blog\/how-anti-ageing-drugs-could-boost-covid-vaccines-in-older-people\/","title":{"rendered":"How anti-ageing drugs could boost COVID vaccines in older people"},"content":{"rendered":"\n\n\n

Source – https:\/\/www.nature.com\/<\/p>\n

COVID-19 poses the greatest threat to older people, but vaccines often don\u2019t work well in this group. Scientists hope drugs that rejuvenate the immune system will help.<\/p>\n

Unlike fine wine, the human body does not improve with age. Hearing fades, skin sags, joints give out. Even the body\u2019s immune system loses some of its vigour.<\/p>\n

This phenomenon, known as immunosenescence, might explain why older age groups are so hard-hit by COVID-19. And there is another troubling implication: vaccines, which incite the immune system to fight off invaders, often perform poorly in older people. The best strategy for quelling the pandemic might fail in exactly the group that needs it most.<\/p>\n

Scientists have known for decades that ageing immune systems can leave the body prone to infection and weaken their response to vaccines. In June, the US Food and Drug Administration announced that a COVID-19 vaccine would have to protect at least half the vaccinated individuals to be considered effective, but protection in older adults might not even meet that bar. \u201cNo vaccine is going to be as effective in the elderly as it is in young people,\u201d says Matt Kaeberlein, a gerontologist at the University of Washington in Seattle. \u201cThat\u2019s an almost certainty.\u201d<\/p>\n

The human immune system is mind-bendingly complex, and ageing affects nearly every component. Some types of immune cell become depleted: for example, older adults have fewer naive T cells that respond to new invaders, and fewer B cells, which produce antibodies that latch on to invading pathogens and target them for destruction. Older people also tend to experience chronic, low-grade inflammation, a phenomenon known as inflammageing (see \u2018Depleted defences\u2019). Although some inflammation is a key part of a healthy immune response, this constant buzz of internal activation makes the immune system less responsive to external insults. \u201cThis overarching, chronic inflammatory state is what\u2019s driving much of the immune dysfunction that we see,\u201d says Kaeberlein. The upshot is a poorer reaction to infections and a dulled response to vaccines, which work by priming the immune system to fight off a pathogen without actually causing disease.<\/p>\n

With about 50 COVID-19 vaccine candidates currently being tested in humans, researchers say it\u2019s not yet clear how they will fare in older adults. In its phase I study of 40 people aged 56 and over, Moderna in Cambridge, Massachusetts, reported that its candidate mRNA-1273 elicited similar antibody levels as those elicited in a younger age group1<\/a><\/sup>. The Chinese biotech Sinovac in Beijing, which trialled its CoronaVac candidate in a phase I\/II study that included 421 adults between 60 and 89 years of age, announced in a press release on 9 September that it seems to work as well in older adults as it does in younger ones. However, a phase I study by international pharma company Pfizer and BioNTech in Mainz, Germany, showed that their vaccine BNT162b2 provokes an immune response that is about half as strong in older adults as it is in younger ones2<\/a><\/sup>. The older adults still produced more antibodies in response to the vaccine than people of a similar age who had had COVID-19, but it\u2019s not known how these levels translate into protection from the virus.<\/p>\n

Most COVID-19 vaccine trials include at least some older adults. But a recent analysis of 18 such trials found that the risk of exclusion is high3<\/a><\/sup>. More than half had age cut-offs and many were at risk of excluding older participants for other reasons, including underlying conditions.<\/p>\n

If COVID-19 vaccines perform less well in older adults, researchers might be able to find ways to tweak the shot itself to elicit a stronger response. Some influenza vaccines, for instance, include immune-boosting ingredients or higher doses of the viral antigen. But some scientists say there is a better option. They are developing and testing drugs that could improve how older adults respond to vaccines and might also help them fight viruses more effectively in the first place. Rather than working with the limitations of the ageing immune system, they are planning to rejuvenate it.<\/p>\n

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