{"id":147965,"date":"2021-01-06T01:35:18","date_gmt":"2021-01-05T22:35:18","guid":{"rendered":"https:\/\/en.buradabiliyorum.com\/why-arent-governments-reserving-second-doses\/"},"modified":"2021-01-06T01:35:18","modified_gmt":"2021-01-05T22:35:18","slug":"why-arent-governments-reserving-second-doses","status":"publish","type":"post","link":"https:\/\/buradabiliyorum.com\/en\/why-arent-governments-reserving-second-doses\/","title":{"rendered":"#Why aren’t governments reserving second doses?"},"content":{"rendered":"

“#Why aren’t governments reserving second doses?<\/strong>”<\/p>\n

\n Vaxx Populi: Modelling suggests nearly 30 per cent of infections could be avoided by front-loading the distribution of first doses\n <\/div>\n
\n On Tuesday, the Ontario government announced that it would vaccinate all residents, workers and essential caregivers in long-term care (LTC) facilities in the hotspots of Toronto, Peel and York Regions as well as Windsor-Essex by Jan. 21.<\/p>\n

One reason for the accelerated\u00a0vaccination plans in Ontario<\/a>, Quebec<\/a>,\u00a0Alberta<\/a>\u00a0and elsewhere, is,\u00a0in part, thanks to a change in procedure that could have a huge impact on the course of the pandemic: they\u00a0are no longer automatically reserving 50 per cent of doses in freezers for the required second jab, but instead assuming future supplies will be sufficient for those second doses (the Pfizer vaccine requires a second dose three weeks after the first, while the Moderna vaccine requires one four weeks later).<\/p>\n

RELATED:\u00a0My mom turns 80 this summer. Can we plan a party, now that Canada has COVID-19 vaccines?<\/strong><\/p>\n<\/blockquote>\n

One reason for the change is research pointing to its benefits, including modelling done by Dr. Ashleigh Tuite, infectious disease epidemiologist at the University of Toronto. In a study she co-authored, published today in the Annals of Internal Medicine<\/em><\/a>, Tuite showed that front-loading the distribution of first doses by allocating the vast majority of the first weeks\u2019 worth of vaccines could mean an additional 23-29 per cent of COVID-19 cases would be averted compared with the previous \u201creserve\u201d strategy.<\/p>\n

\u201cThe people who are going to benefit the most are those who are older and in long-term care homes,\u201d Tuite told Maclean\u2019s<\/em>. \u201cWe have this vaccine now, and, if we use it strategically, we can prevent a lot of infections and a lot of deaths in those settings.\u201d<\/p>\n

Her mathematical modelling focused on Pfizer\u2019s vaccine, which has an official efficacy of 52.4 per cent after the first dose. The modelling projected what would happ<\/a>en over eight weeks, reserving just 10 per cent of supply for second doses during the first three weeks; 90 per cent during the subsequent three weeks; and 50 per cent in the weeks after that. (Tuite and her co-authors modelled only the first two months of vaccine delivery when supplies are most limited, and it assumes everyone gets two doses.)<\/p>\n

RELATED:\u00a0Who is next in line for the vaccine in Canada?<\/strong><\/p>\n<\/blockquote>\n

The study came out of a conversation she had with a co-author, Josh Salomon of Stanford University,\u00a0about the original reserve strategy. \u201cBased on back-of-the-envelope calculations, it seems like you would never really want to do that,\u201d she says, \u201cif you have a vaccine that provides protection even with the first dose.\u201d So they decided out to examine that\u00a0\u201cstraightforward analytic type of question.\u201d<\/p>\n

\u201cIt makes sense,\u201d she said of the\u00a0new, more flexible strategy. \u201cYou have a tool that prevents severe infection. It makes sense to front-load this and get as many people protected, even if they aren\u2019t maximally protected, as soon as possible.\u201d The new process \u201ccontinued to produce greater overall benefits than the fixed strategy even [in a hypothetical scenario in which] we assumed that protection would drop to zero if the second dose was not received within six weeks after the first dose,\u201d the study concluded<\/a>. Indeed, the only scenario in which the older strategy made more sense was if the effectiveness of the first dose proved to be far lower than previously recorded and the supply of doses collapsed.<\/p>\n

RELATED:\u00a0COVID-19 in Canada: How our battle against the second wave is going<\/strong><\/p>\n<\/blockquote>\n

Just before Christmas, she presented her projections to the Ontario COVID-19 Science Advisory Table<\/a>. The table did a separate analysis on adopting such a flexible delivery strategy and came up with very similar findings to those of Tuite, she said. On Dec. 28,Ontario scrapped its second-dose reserve policy<\/a>.<\/p>\n

Since then, the situation in Ontario\u2019s long-term care homes has deteriorated: there are now outbreaks at 216 such homes in Ontario<\/a>, more than occurred at the worst of the spring wave<\/a>, which devastated the sector and resulted in the deaths of nearly 2,000 residents<\/a>. Now, at least, there is hope that many of those living and working in hardest-hit LTC homes will be protected as soon as possible.<\/p>\n

As Canada rolls out the country\u2019s most complex vaccination project to date, <\/em>Maclean\u2019s presents <\/em>Vaxx Populi, an ongoing series<\/a> in which Patricia Treble tackles the most pressing questions related to the new COVID-19 vaccines. Send us a question you\u2019d like answered at vaccines@macleans.ca. If you have specific questions about your own health, we recommend consulting a family doctor or the local public health authority in your area.<\/em>
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