LONDON, Jan 27 (Reuters) - Mass government bond buying programmes by the European Central Bank, U.S. Federal Reserve and other top central banks will protect the credit ratings of most developed economies this year but poorer nations will not be so fortunate, S&P Global says. The coronavirus crisis is expected to push the debt-to-gross domestic product (GDP) ratios in the G7 group of rich nations up by 23 percentage points by the end of 2021 compared to 2019, without yet triggering a cut in their credit ratings, a measure of a country’s fiscal health. But among less developed nations, ratings have been cut over the past year for eight African countries, five Middle East states and 11 South American, central American and Caribbean countries, and more downgrades are on the way, S&P Global says. At present, 16 emerging market (EM) countries still have negative outlooks on their S&P ratings, signalling they could face a downgrade, while fast-rising debt levels in Brazil and South Africa are not expected to stabilise even by 2023. Speaking before the release of a 2021 sovereign outlook, one of S&P’s top sovereign analysts, Frank Gill, told Reuters he expected 2021 would “see a lot more rating actions in EM”. “That doesn’t mean that developed economies are getting a pass. It just means that they have bought themselves more time,” he said. In the euro zone, the ECB’s bond buying programme has been hoovering up the equivalent of all the extra debt issued by the bloc’s 27 members to combat the coronavirus crisis. Assessing the situation in richer nations, Gill said: “Are we going to rush to any conclusions about the permanent damage to structural growth? Highly unlikely.” “So I don’t think you’re going to see a lot of rating actions in the OECD in 2021,” he said. The Organisation for Economic Co-operation and Development groups 37 countries, stretching from the United States to European nations to Japan and Australia.